SEAS Standing Faculty Research Directory
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Ritesh Agarwal
Assistant Professor of Materials Science and Engineering
Email: riteshag at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
I am primarily interested in the studies of the properties of self-assembled nanostructured materials ranging from molecular to macroscopic length scales with a goal of developing the bottom-up paradigm to assemble virtually any kind of a functional system ranging from integrated photonics and electronics to chemical or biological sensors. The underlying theme of my research interests centers on rational synthesis of nanomaterials with accurate control over dimension and composition, detailed understanding of the modified properties of materials at the nanoscale, development of novel device technologies based on the unique properties of nanomaterials, and the integration of nanostructures on a common platform during the assembly process with exquisite spatial control.

Specfic Research Areas include:
1) Growth and characterization of complex but precisely defined nanowire heterostructures for the assembly of novel nanophotonic devices based on quantum confinement effects.

2) Evolve schemes for the assembly of nanostructured materials into complex, yet well controlled patterns by combining the holographic optical tweezer (HOT) technique with other chemical, physical or biological based assembly approaches.

3) Nanoscale phase transitions in Ge-Sb-Te nanowires.

Selected Recent Publications:
S-H. Lee, Y. Jung and R. Agarwal, "Highly-scalable nonvolatile and ultra-low power phase-change nanowire memory", Nature Nanotech., Submitted.

Y. Jung, D-K. Ko and R. Agarwal, "Synthesis and structural characterization of single-crystalline branched nanowire heterostructures," Nano Letters 7 (2), 264-268 (2007).

R. Agarwal and C. M. Lieber, "Semiconductor nanowires: optics and optoelectronics," Applied Physics A-Materials Science & Processing 85 (3), 209-215 (2006).

Y. Jung et al., "Synthesis and characterization of Ge2Sb2Te5 nanowires with memory switching effect," J.Am.Chem.Soc. 128 (43), 14026-14027 (2006).

S. H. Lee et al., "Size-dependent phase transition memory switching behavior and low writing currents in GeTe nanowires," Appl.Phys.Lett. 89 (22), 223116 (2006).

O. Hayden*, R. Agarwal*, and C.M. Lieber, "Nanoscale avalanche photodiodes for highly sensitive and spatially resolved photon detection", Nature Mater., 5, 352 (2006). (*equal contribution, Cover article)

R. Agarwal, K. Ladavac, Y. Roichman, G. Yu, C. M. Lieber & D. G. Grier," Assembling Semiconductor Nanowire Heterostructures with Holographic Optical Traps," Opt. Express 13, 8906 (2005).

R. Agarwal, C. J. Barrelet and C. M. Lieber, "Lasing Mechanism in Single Cadmium Sulfide Nanowire Optical Cavities," Nano Lett. 5, 917 (2005).

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Rajeev Alur
Zisman Family Professor of Computer and Information Science
Email: alur at cis.upenn.edu
Personal Website

Research Interests:
Design tools for embedded software, Formal modeling and verification of reactive systems, Model checking, Hybrid systems, Distributed computing, Logic and automata theory.

Selected Recent Publications:
R. Alur and A. Chandrashekharapuram, "Dispatch sequences for embedded control models," Journal of Computer and System Sciences 73 (2), 156-170 (2007).

R. Alur and M. Bernadsky, "Bounded model checking for GSMP models of stochastic real-time systems," Hybrid Systems: Computation and Control, Proceedings 3927, 19-33 (2006).

R. Alur, P. Cerny and S. Zdancewic, "Preserving secrecy under refinement," Automata, Languages and Programming, Pt 2 4052, 107-118 (2006).

R. Alur, S. Chaudhuri and P. Madhusudan, "Languages of nested trees," Computer Aided Verification, Proceedings 4144, 329-342 (2006).

R. Alur, S. Chaudhuri and P. Madhusudan, "A fixpoint calculus for local and global program flows," Acm Sigplan Notices 41 (1), 153-165 (2006).

R. Alur, T. Dang and F. Ivancic, "Counterexample-guided predicate abstraction of hybrid systems," Theor.Comput.Sci. 354 (2), 250-271 (2006).

R. Alur et al., "Compositional modeling and refinement for hierarchical hybrid systems," Journal of Logic and Algebraic Programming 68 (1-2), 105-128 (2006).

R. Alur, S. La Torre and P. Madhusudan, "Modular strategies for recursive game graphs," Theor.Comput.Sci. 354 (2), 230-249 (2006).

R. Alur and P. Madhusudan, "Adding nesting structure to words," Developments in Language Theory, Proceedings 4036, 1-13 (2006).

S. Burckhardt, R. Alur and M. M. K. Martin, "Bounded model checking of concurrent data types on relaxed memory models: A case study," Computer Aided Verification, Proceedings 4144, 489-502 (2006).

S. Burckhardt, R. Alur and M. M. K. Martin, "Bounded model checking of concurrent data types on relaxed memory models: A case study," Computer Aided Verification, Proceedings 4144, 489-502 (2006).

W. Nam and R. Alur, "Learning-based symbolic assume-guarantee reasoning with automatic decomposition," Automated Technology for Verification and Analysis, Proceedings 4218, 170-185 (2006).

Wonhong Nam and Rajeev Alur, in 4th International Symposium on Automated Technology for Verification and Analysis, ATVA 2006, Anonymous (Springer Verlag, Heidelberg, D-69121, Germany, Beijing, China, 2006) pp. 170-185.

R. Alur, "The benefits of exposing calls and returns," Concur 2005 - Concurrency Theory, Proceedings 3653, 2-3 (2005).

R. Alur et al., "Analysis of recursive state machines," Acm Transactions on Programming Languages and Systems 27 (4), 786-818 (2005).

R. Alur et al., "Synthesis of interface specifications for Java classes," Acm Sigplan Notices 40 (1), 98-109 (2005).

R. Alur, K. Etessami and M. Yannakakis, "Realizaability and verification of MSC graphs," Theor.Comput.Sci. 331 (1), 97-114 (2005).

R. Alur et al., "Congruences for visibly pushdown languages," Automata, Languages and Programming, Proceedings 3580, 1102-1114 (2005).

R. Alur et al., "Congruences for visibly pushdown languages," Automata, Languages and Programming, Proceedings 3580, 1102-1114 (2005).

R. Alur, S. La Torre and P. Madhusudan, "Perturbed timed automata," Hybrid Systems: Computation and Control 3414, 70-85 (2005).

R. Alur, P. Madhusudan and W. Nam, "Symbolic compositional verification by learning assumptions," Computer Aided Verification, Proceedings 3576, 548-562 (2005).

R. Alur, K. McMillan and D. Peled, "Deciding global partial-order properties," Formal Methods Syst.Des. 26 (1), 7-25 (2005).

S. Burckhardt, R. Alur and M. M. K. Martin, "Verifying safety of a token coherence implementation by parametric compositional refinement," Verification, Model Checking, and Abstract Interpretation, Proceedings 3385, 130-145 (2005).

S. Burckhardt, R. Alur and M. M. K. Martin, "Verifying safety of a token coherence implementation by parametric compositional refinement," Verification, Model Checking, and Abstract Interpretation, Proceedings 3385, 130-145 (2005).

Z. J. Yang and R. Alur, "Variable reuse for efficient image computation," Formal Methods in Computer-Aided Design, Proceedings 3312, 430-444 (2004).



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Paulo Arratia
Assistant Professor of Mechanical Engineering and Applied Mechanics
Email: parratia at seas.upenn.edu
   |   Research Website

Research Interests:
The field of Transport Phenomena and Soft-Condensed Matter, in particular fluid mechanics, complex fluids, microfluidics, and interfacial phenomena. My research aims to understand fluid manipulation & dynamics at the meso-, micron- and nanoscales, and interactions between applied forces (e.g. shear) and fluid response.

Selected Recent Publications:
P. E. Arratia, J. P. Gollub, and D. J. Durian, "Polymer filament thinning & breakup in microchannels", PHYS. REV. E, in press, (2007).

P.E. Arratia, J.P. Gollub, and D.J. Durian, "Polymer drop breakup", CHAOS (2007) - GALLERY OF NONLINEAR IMAGES.

P. E. Arratia, C. C. Thomas, J. D. Diorio, and J.P Gollub, "Elastic instabilities of polymeric solutions in cross-channel flows", PHYS. REV. LETT. 96, 144502 (2006).

P. E. Arratia and J. P. Gollub, "Predicting the progress of diffusively limited chemical reactions in the presence of chaotic advection", PHYS. REV. LETT. 96, 024501 (2006).

P. E. Arratia, J. L. Kukura, J. Lacombe, and F.J. Muzzio, "Mixing of shear-thinning fluids with yield-stress in stirred tanks", AIChE J. 52, 2310-2322 (2006).

P. E. Arratia, N. H. Duong, F. J. Muzzio, et al., "A study of the mixing & segregation mechanisms in the Bohle blender via DEM simulations" POWDER TECH. 164, 50-57(2006).

P.E. Arratia, N.H. Duong, F.J. Muzzio, et al., "Characterizing mixing and lubrication in the Bohle bin blender", POWDER TECH. 161, 202-208, (2006).

P. E. Arratia, G. A. Voth, and J. P. Gollub, "Stretching and mixing of non-Newtonian fluids in time-periodic flows", PHYS. FLUIDS 17, 053102 (2005).

P. E. Arratia and J. P. Gollub, "The statistics of stretching distributions in experimental fluid flows exhibiting chaotic advection", J. STAT. PHYS. 121, 805-822, (2005).

O. S. Sudah, P. E. Arratia, A. Alexander, and F.J. Muzzio, "Experiments and 3-D DEM simulations of mixing and segregation in the Gallay tote blender", AIChE J. 51, 836-844 (2005).

P. E. Arratia, T. Shinbrot, M. M. Alvarez, and F.J. Muzzio, "Mixing of non-Newtonian fluids in steadily forced flows", PHYS. REV. LETT. 94, 084501 (2004).

P.E. Arratia, T. Shinbrot, and F.J. Muzzio, "Three dimensional chaotic mixing", PHYS. FLUIDS. 16, (2004) - GALLERY OF FLUID MOTION.

P.E. Arratia, F.J. Muzzio, "Planar laser-induced fluorescence method for analysis of mixing in laminar flows", IND. ENG. CHEM. RES. 43, 6557-6568, (2004).

P.E. Arratia, T. Shinbrot, J.P. Lacombe, and F.J. Muzzio, "Segregated regions in continuous laminar stirred tank reactors", CHEM. ENG. SCI. 59,1481-1490, (2004).

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P. S. Ayyaswamy
Asa Whitney Professor of Dynamical Engineering; Graduate Group Chair
Email: ayya at seas.upenn.edu
Personal Website

Research Interests:
Interconnection processes in microelectronic packaging technology: wire and die bonding: We have been investigating the melting of metals and alloys by arc-discharges and subsequent solidification. This is in regard to microelectronic interconnection by wire bonding. Recently we have extended these studies to include plasma spraying/etching. With regard to die-bonding, we have established new results for the flow of yield stress fluids. Microgravity fluid mechanics, mass transfer, and biotechnology: Here our objective has been to determine the mechanisms responsible for changes in osteoblast behavior under simulated microgravity conditions by employing experimental and numerical/analytical methods. We have conducted in vitro experiments with osteoblasts in the rotating wall vessels to assess the effects of both gravity and hydrodynamic shear stresses on the function of bone cells. Convective heat and mass transfer in the presence of a phase-change: We have been investigating forced convection effects on condensation, evaporation and combustion. Study of transport associated with moving liquid drops is emphasized. We are also studying the effect of electric fields on flames under normal and microgravity conditions.

Selected Recent Publications:
P. S. Ayyaswamy and K. Mukundakrishnan, "Optimal conditions for simulating microgravity employing NASA designed rotating wall vessels," Acta Astronaut. 60 (4-7), 397-405 (2007).

P. S. Ayyaswamy, J. Zhang and D. M. Eckmann, "Numerical modeling of the transport to an intravascular bubble in a tube with a soluble," Interdisciplinary Transport Phenomena in the Space Sciences 1077, 270-287 (2006).

D. M. Eckmann et al., "Gas embolism and surfactant-based intervention - Implications for long-duration space-based activity," Interdisciplinary Transport Phenomena in the Space Sciences 1077, 256-269 (2006).

S. V. Lynch et al., "Escherichia coli biofilms formed under low-shear modeled microgravity in a ground-based system," Appl.Environ.Microbiol. 72 (12), 7701-7710 (2006).

J. Zhang, D. M. Eckmann and P. S. Ayyaswamy, "A front tracking method for a deformable intravascular bubble in a tube with soluble surfactant transport," Journal of Computational Physics 214 (1), 366-396 (2006).

M. L. Parker, B. L. Drolen and P. S. Ayyaswamy, "Loop heat pipe for spacecraft thermal control, part 2: Ambient condition tests," J.Thermophys.Heat Transfer 19 (2), 129-136 (2005).

M. A. Bucaro et al., "Bone cell survival in microgravity - Evidence that modeled Microgravity increases osteoblast sensitivity to apoptogens," Transport Phenomena in Microgravity 1027, 64-73 (2004).

M. A. Bucaro et al., "A novel alginate carrier system to evaluate osteoblast apoptosis in vector-averaged gravity using rotating wall vessels." Journal of Bone and Mineral Research 19, S392-S392 (2004).

K. Mukundakrishnan et al., "Modeling of phosphate ion transfer to the surface of osteoblasts under normal gravity and simulated microgravity conditions," Transport Phenomena in Microgravity 1027, 85-98 (2004).

Q. Q. Qiu, P. Ducheyne and P. S. Ayyaswamy, "Bioactive, degradable composite microspheres: effect of filler material on surface reactivity," Ann.N.Y.Acad.Sci. 974, 556-564 (2002).



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Norman I. Badler
Professor of Computer and Information Science; Director, Center for Human Modeling and Simulation; Associate Dean of the School of Engineering and Applied Science
Email: badler at seas.upenn.edu
Personal Website

Research Interests:
Computer graphics, human movement simulation, embodied agents, three-dimensional virtual and augmented reality interaction; and relationships between human movement, natural language, instructions and communication.

Selected Recent Publications:
E. Gu and N. I. Badler, "Visual attention and eye gaze during multiparty conversations with distractions," Intelligent Virtual Agents, Proceedings 4133, 193-204 (2006).

N. Pelechano and N. I. Badler, "Modeling crowd and trained leader behavior during building evacuation," IEEE Comput.Graphics Appl. 26 (6), 80-86 (2006).

E. Gu, C. Stocker and N. I. Badler, "Do you see what eyes see? Implementing inattentional blindness," Intelligent Virtual Agents, Proceedings 3661, 178-190 (2005).

L. W. Zhao and N. I. Badler, "Acquiring and validating motion qualities from live limb gestures," Graphical Models 67 (1), 1-16 (2005).



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John L. Bassani
Richard H. and S. L. Gabel Professor of Mechanical Engineering; Professor of Materials Science and Engineering
Email: bassani at seas.upenn.edu
Personal Website

Research Interests:
Plastic Deformation of Crystals: Plastic deformation of crystalline solids, including ordered compounds and multiphase materials, is investigated. Strain localization is studied under multiple slip deformations. Nonlocal effects that give rise both to size-dependent phenomena and patterning of localized flow are also investigated utilizing both continuum theories and discrete dislocation simulations. Interface Mechanics: The relationship between atomic-level (discrete) and continuum properties of heterogeneous solids is studied. In particular, the spatially-varying (anisotropic) elastic properties of interfaces and their effect on lattice vibrations (phonons) and localized waves are investigated. The implication of distinct atomic structures on interface diffusion is being explored in relation to another current interest in decohesion along interfaces. Fracture: Fracture along interfaces is studied from several perspectives with recent interest in dynamic embrittlement arising from impurity diffusion. Atomistic simulations are utilized to guide the continuum modeling of this thermodynamically non-equilibrium process. Models for crack propagation are being developed and compared with experiments.

Selected Recent Publications:
V. Racherla and J. L. Bassani, "Strain burst phenomena in the necking of a sheet that deforms by non-associated plastic flow," Modell Simul Mater Sci Eng 15 (1), S297-S311 (2007).

V. Vitek et al., "Effects of non-glide stresses on the plastic flow of single and polycrystals of molybdenum," Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing 387-89, 138-142 (2004).

V. Vitek et al., "Effects of non-glide stresses on the plastic flow of single and polycrystals of molybdenum," Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing 387-89, 138-142 (2004).



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Haim H. Bau
Professor of Mechanical Engineering and Applied Mechanics; Professor of Electrical and Systems Engineering
Email: bau at seas.upenn.edu
Personal Website

Research Interests:
Active Control of Flow Patterns: Often, in industrial processes and in propulsion, fluids behave in an undesirable way. For example, oscillatory convection in a crystal melt leads to defects in the crystal. Conversely, in chemical reactions and combustion, it is desirable to maintain chaotic and turbulent flows to achieve vigorous mixing. Applying ideas of control theory, we are studying experimentally and theoretically the feasibility of modifying flow patterns so as to achieve optimal flow conditions for various processes. For example, with the use of a feedback controller effecting small perturbations in boundary conditions, we have been able to maintain laminar flows under conditions in which chaotic flows would normally occur and conversely, induce chaos under conditions when the flow would normally tend to be laminar. Micro-fluidics: In experiment and theory, we are studying transport processes in very small devices and we are developing various microfluidic components. The objective is to develop the necessary science base needed to accommodate biological and chemical laboratories on a "chip." Among other things, we are developing micro mixers, inertial separators of particles, thermal cyclers, and electrophoretic cells. Most recently, our efforts have focused on constructing MEMS devices on low-temperature, co-fired, ceramic tapes.

Selected Recent Publications:
M. E. Arsenault et al., "Manipulation and stiffness determination of actin filaments in oscillating electric fields," Biophys.J. , 140A-140A (2007).

H. Liu, S. Z. Qian and H. H. Bau, "The effect of translocating cylindrical particles on the ionic current through a nanopore," Biophys.J. 92 (4), 1164-1177 (2007).

M. C. Remillieux, H. Zhao and H. H. Bau, "Suppression of Rayleigh-Benard convection with proportional-derivative controller," Phys.Fluids 19 (1), 017102 (2007).

S. Sinha et al., "Induction and measurement of minute flow rates through nanopipes," Phys.Fluids 19 (1), 013603 (2007).

H. Zhao and H. H. Bau, "On the effect of induced electro-osmosis on a cylindrical particle next to a surface," Langmuir 23 (7), 4053-4063 (2007).

D. Mattia et al., "Effect of graphitization on the wettability and electrical conductivity of CVD-carbon nanotubes and films," J Phys Chem B 110 (20), 9850-9855 (2006).

S. Z. Qian et al., "Electrochemical reaction with RedOx electrolyte in toroidal conduits in the presence of natural convection," Int.J.Heat Mass Transfer 49 (21-22), 3968-3976 (2006).

M. Riegelman, H. Liu and H. H. Bau, "Controlled nanoassembly and construction of nanofluidic devices," Journal of Fluids Engineering-Transactions of the Asme 128 (1), 6-13 (2006).

J. Wang et al., "A disposable microfluidic cassette for DNA amplification and detection," Lab on a Chip 6 (1), 46-53 (2006).

H. Zhao and H. H. Bau, "Limitations of linear control of thermal convection in a porous medium," Phys.Fluids 18 (7), 074109 (2006).

Z. Y. Chen et al., "Thermally-actuated, phase change flow control for microfluidic systems," Lab on a Chip 5 (11), 1277-1285 (2005).

B. M. Kim, T. Murray and H. H. Bau, "The fabrication of integrated carbon pipes with sub-micron diameters," Nanotechnology 16 (8), 1317-1320 (2005).

B. M. Kim, S. Qian and H. H. Bau, "Filling carbon nanotubes with particles," Nano Letters 5 (5), 873-878 (2005).

S. Qian and H. H. Bau, "Magnetohydrodynamic flow of RedOx electrolyte," Phys.Fluids 17 (6), 067105 (2005).

S. Qian and H. H. Bau, "Magneto-hydrodynamic stirrer for stationary and moving fluids," Sensors and Actuators B-Chemical 106 (2), 859-870 (2005).

S. Z. Qian and H. H. Bau, "Theoretical investigation of electro-osmotic flows and chaotic stirring in rectangular cavities," Appl.Math.Model. 29 (8), 726-753 (2005).

S. Z. Qian, R. Burger and H. H. Bau, "Analysis of sedimentation biodetectors," Chemical Engineering Science 60 (10), 2585-2598 (2005).

J. Wang et al., "Self-actuated, thermo-responsive hydrogel valves for lab on a chip," Biomed.Microdevices 7 (4), 313-322 (2005).

J. Wang et al., "Self-actuated, thermo-responsive hydrogel valves for lab on a chip," Biomed.Microdevices 7 (4), 313-322 (2005).

J. Wang et al., "Self-actuated, thermo-responsive hydrogel valves for lab on a chip," Biomed.Microdevices 7 (4), 313-322 (2005).



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George Biros
Assistant Professor of Mechanical Engineering and Applied Mechanics; Assistant Professor of Computer and Information Science
Email: biros at seas.upenn.edu
Personal Website

Research Interests:
Computational science and engineering; optimization; bioengineering; parallel computing.

Selected Recent Publications:
V. Akcelik et al., "Inversion of airborne contaminants in a regional model," Computational Science - Iccs 2006, Pt 3, Proceedings 3993, 481-488 (2006).

L. X. Ying, G. Biros and D. Zorin, "A high-order 3D boundary integral equation solver for elliptic PDEs in smooth domains," Journal of Computational Physics 219 (1), 247-275 (2006).



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Matthew Blaze
Associate Professor of Computer and Information Science
Email: blaze at cis.upenn.edu
Personal Website

Research Interests:
Secure Systems and Cryptology - My research focuses on the architecture and design of secure systems based on cryptographic techniques, analysis of secure systems against practical attack models, and on finding new cryptographic primitives and techniques. This work has led directly to several new cryptographic concepts, including: "Remotely-Keyed Encryption," which allows the use of inexpensive, low-bandwidth secure hardware to protect high-bandwidth communication and stored data, "Atomic Proxy Cryptography," which allows re-encryption by untrusted third parties, and "Master-Key Encryption," which provides a systematic way to design (and study) ciphers with built-in "back doors." I am especially interested in the use of encryption to protect insecure systems such as the Internet. I was a designer of swIPe, a predecessor of the now standard IPSEC protocol for protecting Internet traffic. Another project, CFS, investigated and demonstrated the feasibility of including encryption as file system service. Recently, I've applied cryptologic techniques to other areas, including the analysis of physical security systems; this work yielded a powerful and practical attack against virtually all commonly used master-keyed mechanical locks. Trust Management: I coined the term, and am one of the inventors of, Trust Management, which provides the abstract layer in which a system decides whether to allow some potentially dangerous action. This work has led to two trust management languages, KeyNote and PolicyMaker, that provide tools for specifying policy, delegating authority, and controlling access. In addition to providing a useful framework for studying and proving security properties of distributed systems, our tools have been used to build powerful policy control mechanisms into several important applications, including the OpenBSD IPSEC implementation. Technology and Public Policy: Cryptology and computer security have important relationships to vital areas of public policy, and my work has touched on these in several ways. In 1994, I discovered a serious flaw in the US Government's "Clipper" encryption system, which had been proposed as a mechanism for the public to encrypt their data in a way that would still allow access by law enforcement. I have edited several influential reports on encryption policy, including the 1998 study of "key escrow" systems that demonstrated that such systems are inherently less secure and more expensive than systems without such a feature. This work contributed to the recent shift in U.S. encryption policy. More recently, I have been active in the analysis of the FBI's "Carnivore'' Internet wiretap system. I have testified before various comittees of the US Congress and European Parliament several times, providing technical perspective on the problems surrounding law enforcement and intelligence access to communications traffic and computer data.

Selected Recent Publications:
M. Blaze, "Toward a broader view of security protocols," Security Protocols 3957, 106-132 (2006).

S. M. Bellovin, M. Blaze and S. Landau, "The real national-security needs for VolP," Commun ACM 48 (11), 120-120 (2005).

M. Sherr et al., "Signaling vulnerabilities in wiretapping systems," Ieee Security & Privacy 3 (6), 13-25 (2005).



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Eric T. Boder
Assistant Professor of Chemical and Biomolecular Engineering
Email: boder at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Development and optimization of proteins as therapeutic agents; engineering the immune response; biophysics and structural biology of immunological receptors; high affinity protein binding. Proteins are naturally occurring polymers comprised of amino acid subunits. The advantage of these molecules is their ability to catalyze a wide range of complex chemistries and engage in countless exquisitely specific molecular interactions, yet each protein is itself constructed from a single synthetic chemistry and its function is perfectly contained within a simple genetic code. The ability of this class of molecule to perform highly complex tasks, combined with their relative ease of synthesis by microorganisms, has spurred the development of an industry pursuing the use of proteins in separations, diagnostics, and numerous medical therapies. Protein pharmaceuticals, also called biopharmaceuticals, represent a rapidly developing product area in industry. In many cases, the extreme specificity of molecular interations required to inhibit certain disease states has limited the success of small organic pharmaceuticals in treatment. Protein reagents have the potential to overcome this obstacle; however, the utility of proteins as therapeutic agents has been limited by the lack of a quantitative engineering approach to developing proteins with the appropriate molecular properties. My goal is to develop a program of research addressing this need. This research must consider several critical points: 1. Selection of a molecular scaffold with properties suitable for the intended application (e.g, tissue penetration properties, thermal stability); 2. Development of protein engineering processes for quantitatively altering the functional properties of the chosen reagent to optimize for the specific application; 3. Quantitative analysis of the relevant molecular properties and combination of this knowledge with protein engineering processes for molecular design. A particular target application of this research is engineering the immune response. Numerous devastating diseases result from destruction of the body's own tissues due to attack by the cellular immune system (autoimmunity). Misidentification of self in autoimmunity and immunological attack of transplanted tissues, as well as failure of the immune system to identify certain harmful entities (e.g., certain viruses or tumor cells), is essentially a problem of molecular recognition. Inhibiting undesirable immune responses or stimulating immune responses against novel targets are problems most likely to be solved by taking advantage of the unique properties of engineered protein reagents. Research in this area makes use of tools from molecular biology, protein chemistry, and biophysics.

Selected Recent Publications:
R. Parthasarathy, S. Subramanian and E. T. Boder, "Sortase A as a novel molecular "stapler" for sequence-specific protein conjugation," Bioconjug.Chem. 18 (2), 469-476 (2007).

S. Subramanian, E. T. Boder and D. E. Discher, "Phylogenetic divergence of CD47 interactions with human signal regulatory protein alpha reveals locus of species specificity - Implications for the binding site," J.Biol.Chem. 282 (3), 1805-1818 (2007).

P. Derr, E. Boder and M. Goulian, "Changing the specificity of a bacterial chemoreceptor," J.Mol.Biol. 355 (5), 923-932 (2006).

S. Park et al., "Limitations of yeast surface display in engineering proteins of high thermostability," Protein Engineering Design & Selection 19 (5), 211-217 (2006).

R. Parthasarathy et al., "Post-translational regulation of expression and conformation of an immunoglobulin domain in yeast surface display," Biotechnol.Bioeng. 93 (1), 159-168 (2006).

L. R. Pepper, D. A. Hammer and E. T. Boder, "Rolling adhesion of alpha(L) I domain mutants decorrelated from binding affinity," J.Mol.Biol. 360 (1), 37-44 (2006).

S. Subramanian et al., "Species- and cell type-specific interactions between CD47 and human SIRP alpha," Blood 107 (6), 2548-2556 (2006).

E. T. Boder et al., "Yeast surface display of a noncovalent MHC class II heterodimer complexed with antigenic peptide," Biotechnol.Bioeng. 92 (4), 485-491 (2005).

S. Park, E. T. Boder and J. G. Saven, "Modulating the DNA affinity of Elk-1 with computationally selected mutations," J.Mol.Biol. 348 (1), 75-83 (2005).

S. Park et al., "Progress in the development and application of computational methods for probabilistic protein design," Comput.Chem.Eng. 29 (3), 407-421 (2005).

R. Parthasarathy, J. Bajaj and E. T. Boder, "An immobilized biotin ligase: Surface display of Escherichia coli BirA on Saccharomyces cerevisiae," Biotechnol.Prog. 21 (6), 1627-1631 (2005).

J. H. Lee et al., "Developing nanomachines via engineering of novel membrane protein," Protein Science 13, 154-155 (2004).

A. W. Nields, S. Park and E. T. Boder, "Heterogeneous truncation of yeast-secreted heterologous proteins," Protein Science 13, 99-100 (2004).

S. Subramanian et al., "CD47-mediated phagocytosis inhibition: Signaling and molecular determinants," Mol.Biol.Cell 15, 65A-65A (2004).



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Daniel K. Bogen
Associate Professor of Bioengineering; Associate Professor of Bioengineering in Medicine; Associate Professor of Rehabilitation Medicine; Associate Professor of Bioengineering in Pediatrics
Email: dan at seas.upenn.edu
Personal Website

Research Interests:
My primary research interest is in pediatric rehabilitation engineering-developing new technology to diagnose and treat disabled children. I am especially interested in cognitive rehabilitation of children with brain injury and other neurological or cognitive disorders. This work involves the development of new kinds of pediatric user-interfaces to biomedical devices-interfaces which are appealing to children, and which allow the children to operate diagnostic and therapeutic instruments.

Selected Recent Publications:
S. K. Lin, S. T. Kuna and D. K. Bogen, "A novel device for measuring long-term oxygen therapy adherence: a preliminary validation," Respir.Care 51 (3), 266-271 (2006).

T. D. Yoo et al., "Geometric and biomechanical analysis for computer-aided design of assistive medical devices," Comput.-Aided Des. 37 (14), 1521-1532 (2005).

D. Bogen and A. J. Apter, "Adherence logger for a dry powder inhaler: a new device for medical adherence research," J.Allergy Clin.Immunol. 114 (4), 863-868 (2004).

T. D. Yoo et al., "Geometrical analysis for assistive medical device design," Computational and Information Science, Proceedings 3314, 916-921 (2004).


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Dawn A. Bonnell
Trustees Chair Professor of Materials Science and Engineering; Professor of Bioengineering; Director of Nano-Bio Interface Center
Email: bonnell at lrsm.upenn.edu
Personal Website   |   Research Website

Research Interests:

Research in the Bonnell Group is focused on the fundamental basis of property variations at nanometer length scales in complex materials and exploiting these variations to make functional nanosystems.

The length scale may be due to the size of the system as in a 3 nm metal cluster, or to the vicinity of a defect such as an atomic interface in a solid or a bonding defect in a molecular wire. The focus on complex materials enables a large range of functional behavior. Our studies involve transition metal oxides, organic and inorganic ferroelectric compounds, functionalized organic and biological molecules, and non conventional semiconductors. New methods of fabrication are required to produce composites of these constituents that are useful for molecular electronics or biochemical sensors.

Selected Recent Publications:
M. P. Nikiforov et al., "Assembly and optoelectrical properties of amphiphilic peptides with chain of cofactors for electron transfer between interfaces," Biophys.J. , 503A-503A (2007).

D. B. Li et al., "Polarization reorientation in ferroelectric lead zirconate titanate thin films with electron beams," J.Mater.Res. 21 (4), 935-940 (2006).

M. Nikiforov et al., "Polarization controlled transport in PANI-BaTiO(3) nanofibers," Nano Lett. 6 (5), 896-900 (2006).

R. Shao and D. A. Bonnell, "Interface mediated transport properties in n-type SrTiO3 : Induced dipole alignment at oxide grain boundaries," Journal of Electroceramics 17 (2-4), 211-219 (2006).

R. Shao, M. P. Nikiforov and D. A. Bonnell, "Photoinduced charge dynamics on BaTiO3(001) surface characterized by scanning probe microscopy," Appl.Phys.Lett. 89 (11), 112904 (2006).

D. R. Strachan et al., "Clean electromigrated nanogaps imaged by transmission electron microscopy," Nano Lett. 6 (3), 441-444 (2006).

S. V. Kalinin, R. Shao and D. A. Bonnell, "Local phenomena in oxides by advanced scanning probe microscopy," J Am Ceram Soc 88 (5), 1077-1098 (2005).

X. J. Lei et al., "In situ deposition," J.Mater.Res. 20 (3), 712-718 (2005).

R. Shao et al., "Low-temperature resistance anomaly at SrTiO3 grain boundaries: evidence for an interface-induced phase transition," Phys.Rev.Lett. 95 (19), 197601 (2005).

C. Staii et al., "High frequency scanning gate microscopy and local memory effect of carbon nanotube transistors," Nano Lett. 5 (5), 893-896 (2005).

D. R. Strachan et al., "Controlled fabrication of nanogaps in ambient environment for molecular electronics," Appl.Phys.Lett. 86 (4), 043109 (2005).

R. Getty et al., "Properties of self-assembled monolayers of aromatic ethynylene oligomers." Abstracts of Papers of the American Chemical Society 228, U426-U426 (2004).

S. V. Kalinin and D. A. Bonnell, "Local electronic transport at grain boundaries in Nb-doped SrTiO3," Physical Review B 70 (23), 235304 (2004).

M. Freitag et al., "Role of single defects in electronic transport through carbon nanotube field-effect transistors," Phys.Rev.Lett. 89 (21), 216801 (2002).

E. A. Kaufmann et al., "Initial events at the bioactive glass surface in contact with protein-containing solutions," J.Biomed.Mater.Res. 52 (4), 825-830 (2000).



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Joseph Bordogna
lfred Fitler Moore Professor of Engineering
Email: bordogna at seas.upenn.edu
Personal Website

Research Interests:
Optoelectronics, manufacturing systems, environmental technologies, management of technological innovation, educational innovation, federal science and engineering policy.

Selected Recent Publications:
Bordogna, J. Time travel to 2029: Nanotechnology. Semiconductor International, v 27, n 1, Jan. 2004, p 40-2.

Bordogna, J. Nano transformations: a future of our making. IEEE International Electron Devices Meeting 2003, 2003, p 1.3.1-4.


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Gershon Buchsbaum
Professor of Bioengineering; Member of the Institute for Neurological Sciences; Member of the Institute for Medicine and Engineering; Member of the Institute for Research in the Cognitive Sciences
Email: gershon at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Visual signal processing and image coding, modeling of retinal and visual system architecture and function, auditory-visual scene analysis, computational neuroscience. Research Techniques: Modeling and simulation; image processing; digital signal processing; neural networks. Research Summary: The neural architecture of the visual system with its unique and elaborate response properties in space, time and color provides us with all the features and richness of our visual world. The main goals of our research are: 1) to understand how the visual neural architecture is matched to the image and how it samples, codes and processes the different features of the image. 2) To identify the attributes of natural images that are most critical for coding in the visual system. Questions we ask are: What are the significant correlations and functional relations among the different image features? How do critical parameters such as contrast in time, space and color and local and global details affect visual image processing? How does visual processing match and adapt to dynamic changes in the image? How does the visual system extract image features such as spatial detail and color? To investigate these questions, we apply quantitative analysis and simulation methods from image processing and neural networks that are rigorously based on known anatomy and physiology and explore the design principles and strategy underlying the visual system neural architecture.

Selected Recent Publications:
G. Buchsbaum and O. Bloch, "Color categories revealed by non-negative matrix factorization of Munsell color spectra," Vision Res. 42 (5), 559-563 (2002).

A. Hsu et al., "Cost of cone coupling to trichromacy in primate fovea," J.Opt.Soc.Am.A Opt.Image Sci.Vis. 17 (3), 635-640 (2000).

R. Rao-Mirotznik, G. Buchsbaum and P. Sterling, "Transmitter concentration at a three-dimensional synapse," J.Neurophysiol. 80 (6), 3163-3172 (1998).

B. Levitan and G. Buchsbaum, "Parallel cone bipolar to on-beta ganglion cell pathways in the cat retina: spatial responses, spatial aliasing, and spatial variance," J.Opt.Soc.Am.A Opt.Image Sci.Vis. 13 (6), 1152-1165 (1996).

S. M. Courtney, L. H. Finkel and G. Buchsbaum, "Network simulations of retinal and cortical contributions to color constancy," Vision Res. 35 (3), 413-434 (1995).

S. M. Courtney, L. H. Finkel and G. Buchsbaum, "Network simulations of retinal and cortical contributions to color constancy," Vision Res. 35 (3), 413-434 (1995).

C. K. Kier, G. Buchsbaum and P. Sterling, "How retinal microcircuits scale for ganglion cells of different size," J.Neurosci. 15 (11), 7673-7683 (1995).

R. Rao-Mirotznik et al., "Mammalian rod terminal: architecture of a binary synapse," Neuron 14 (3), 561-569 (1995).

R. Rao, G. Buchsbaum and P. Sterling, "Rate of quantal transmitter release at the mammalian rod synapse," Biophys.J. 67 (1), 57-63 (1994).

M. P. Eckert and G. Buchsbaum, "Efficient coding of natural time varying images in the early visual system," Philos.Trans.R.Soc.Lond.B.Biol.Sci. 339 (1290), 385-395 (1993).

B. Levitan and G. Buchsbaum, "Signal sampling and propagation through multiple cell layers in the retina: modeling and analysis with multirate filtering," J.Opt.Soc.Am.A 10 (7), 1463-1480 (1993).

B. Lee, M. Litt and G. Buchsbaum, "Rheology of the vitreous body. Part I: Viscoelasticity of human vitreous," Biorheology 29 (5-6), 521-533 (1992).

S. M. Courtney and G. Buchsbaum, "Temporal differences between color pathways within the retina as a possible origin of subjective colors," Vision Res. 31 (9), 1541-1548 (1991).

A. M. Rohaly and G. Buchsbaum, "Global spatiochromatic mechanism accounting for luminance variations in contrast sensitivity functions," J.Opt.Soc.Am.A 6 (2), 312-317 (1989).

A. M. Rohaly and G. Buchsbaum, "Inference of global spatiochromatic mechanisms from contrast sensitivity functions," J.Opt.Soc.Am.A 5 (4), 572-576 (1988).



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Jason A. Burdick
Assistant Professor of Bioengineering
Email: burdick2 at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Developing degradable polymeric biomaterials that can be used for tissue engineering, drug delivery, and fundamental polymer studies. The
platform polymer technology involves the development of multifunctional
monomers that form degradable crosslinked networks via a radical
polymerization. Dr. Burdick's specific research interests include:
scaffolding for cell and growth factor delivery in bone and cartilage
regeneration, controlling stem cell differentiation, growth factor delivery,
and investigating the influence of monomer structure on resulting
network macroscopic and microscopic properties.

Selected Recent Publications:
A.R. Tan, B.M. Baker, J.L. Ifkovits, D.M. Brey, R.L.Mauck, J.A. Burdick, “Electrospinning of Photocrosslinked and Degradable Fibrous Scaffolds,” in preparation.

C. Chung and J.A. Burdick, “Engineering Cartilage Tissue,” Advanced Drug Delivery Reviews, in preparation (invited review).

J.S. Katz and J.A. Burdick, “Hydrogel Mediated Delivery of Trophic Factors for Neural Repair,” Wiley Interdisciplinary Reviews – Nanomedicine, submitted.

P.M. George, R. Saigal, M. Lawlor, M.J. Moore, D.A. LaVan, R. Marini, M. Selig, M. Makhni, J.A. Burdick, R. Langer, D.S. Kohane, “Stand-Alone Three-Dimensional Conductive Constructs for Nerve Regeneration and Other Applications,” submitted.

J.L. Ifkovits and J.A. Burdick, “Photopolymerizable and Degradable Biomaterials for Tissue Engineering Applications,” Tissue Engineering, in press.

D.M. Brey, I. Erickson, and J.A. Burdick, “Influence of Macromer Molecular Weight and Chemistry on Poly(b-amino ester) Network Properties and Initial Cell Interactions,” Journal of Biomedical Materials Research A, in press.

S. Gerecht, J.A. Burdick, L.S. Ferreira, S.A. Townsend, R. Langer, G. Vunjak-Novakovic, “Hyaluronic Acid Hydrogel for Controlled Self-renewal and Differentiation of Human Embryonic Stem Cells,” Proceedings of the National Academy of Sciences (PNAS), 104:11298-11303, 2007.

E. Figallo, C. Cannizzaro, S. Gerecht, J.A. Burdick, R. Langer, N. Elvassore, G. Vunjak-Novakovic, “Micro Bioreactor Array for Controlling Cellular Microenvironments,” Lab on a Chip, 7:710-719, 2007.

S. Gerecht, J.A. Burdick, C. Cannizzaro, G. Vunjak-Novakovic, “3D Cultivation of Human Embryonic Stem Cells,” in Human Embryonic Stem Cells (eds. J. Masters, B. Palsson, J. Thomson), Springer Verlag, 2007.

Y. Yeo, W. Geng, T. Ito, D.S. Kohane, J.A. Burdick, M. Radisic, “Photocrosslinkable Hydrogel for Myocyte Cell Culture and Injection,” Journal of Biomedical Materials Research B, Applied Biomaterials, 81B:312-322, 2007.

A. Khademhosseini, G. Eng, J. Yeh, J. Fukuda, J. Blumling, R. Langer, J.A. Burdick, “Micromolding of Photocrosslinkable Hyaluronic Acid for Cell Encapsulation and Entrapment,” Journal of Biomedical Materials Research A, 79A:522-532, 2006.

D.G. Anderson, C.A. Tweedie, N. Hossain, S.M. Navarro, D.M. Brey, K.J. Van Vliet, R. Langer, J.A. Burdick, “A Combinatorial Library of Photocrosslinkable and Degradable Materials,” Advanced Materials, 18:2614-2618, 2006.

J.A. Burdick*, J. Piantino*, D. Goldberg, R. Langer, L.I. Benowitz, “An Injectable, Degradable Hydrogel for Trophic Factor Delivery Enhances Axonal Rewiring and Improves Performance after Spinal Cord Injury,” Experimental Neurology, 201: 359-367, 2006.

C. Chung, J. Mesa, G.J. Miller, M.A. Randolph, T. Gill, J.A. Burdick, “Effects of Auricular Chondrocyte Expansion on Neocartilage Formation in Photocrosslinkable Hyaluronic Acid Networks,” Tissue Engineering, 12:2665-2673, 2006.

C. Chung, J. Mesa, M.A. Randolph, M. Yaremchuk, J.A. Burdick, “Influence of Gel Properties on Neocartilage Formation by Auricular Chondrocytes Photoencapsulated in Hyaluronic Acid Networks,” Journal of Biomedical Materials Research A, 77A: 518-525, 2006.

Y. Yeo, J.A. Burdick, C.B. Highley, R. Marini, R. Langer, D.S. Kohane, “Peritoneal Application of Chitosan and UV-crosslinkable Chitosan,” Journal of Biomedical Materials Research A, 78A: 668-675, 2006.

P.M. George, D.A. LaVan, J.A. Burdick, C.Y. Chen, E. Liang, R. Langer, “Electrically Controlled Drug Delivery from a Biotin-Doped Conductive Polypyrrole,” Advanced Materials, 18: 577-581, 2006.

J.A. Burdick, M. Ward, E. Liang, M.J. Young, R. Langer, “Stimulation of Neurite Outgrowth by Neurotrophins Delivered from Degradable Hydrogels,” Biomaterials, 27: 452-459, 2006.

J.A. Burdick and Molly M. Stevens, “Biomedical Hydrogels,” in Biomaterials, Artificial Organs, and Tissue Engineering (eds. J. Jones and L. Hench), Woodhead Publishing Ltd., Cambridge, 2005.

B.A. Pfeifer, J.A. Burdick, S. Little, R. Langer, “Poly(ester-anhydride):Poly(b-amino ester) Micro- and Nanospheres: DNA Encapsulation and Cellular Transfection,” International Journal of Pharmaceutics, 304, 210-219, 2005.

J.A. Burdick*, S. Levenberg*, T. Kraehenbuehl, R. Langer, “Neurotrophin Induced Differentiation of Human Embryonic Stem Cells on 3-Dimensional Polymeric Scaffolds,” Tissue Engineering, 11: 506-512, 2005. (*authors contributed equally)

J.A. Burdick, C. Chung, X. Jia, M.A. Randolph, R. Langer, “Controlled Degradation and Mechanical Behavior of Photopolymerized Hyaluronic Acid Networks,” Biomacromolecules, 6: 386-391, 2005.

B.A. Pfeifer, J.A. Burdick, R. Langer, “Formulation and Surface Modification of Poly(Ester-Anhydride) Micro- and Nanospheres,” Biomaterials, 26: 117-124, 2005.

T.M. Lovestead, J.A. Burdick, K.S. Anseth, C.N. Bowman, “Understanding Multivinyl Monomer Photopolymerization Kinetics through Modeling and GPC Investigation of Degradable Networks,” Polymer, 46: 6226-6234, 2005.

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Robert Carpick
Associate Professor of Mechanical Engineering and Applied Mechanics
Email: carpick at seas.upenn.edu
   |   Research Website

Research Interests:
Experimental nanomechanics and nanotribology (friction, adhesion, lubrication, wear). Science and technology of nanostructured materials, including self-assembled monolayers and ultrahard carbon-based films. Development and application of advanced scanning force microscopy tools and surface science techniques.

Selected Recent Publications:
Nanotribology of octadecyltrichlorosilane monolayers and silicon: Self-mated vs. unmated interfaces and local packing density effects, E.E. Flater, W.R. Ashurst, R.W. Carpick, Langmuir, in press (2007).

Mechanical instabilities of individual multi - walled carbon nanotubes under uniaxial loading, H.W. Yap, R.S. Lakes, R.W. Carpick, Nano Lett., 7 (5) 1149-54 (2007).

Small amplitude reciprocating wear performance of diamond-like carbon films: Dependence of film composition and counterface material, J.A. Bares, A.V. Sumant, D.S. Grierson, R.W. Carpick, and K. Sridharan, Tribology Lett., 27 (1) 79-88 (2007).

Atomic-scale friction on diamond: A comparison of different sliding directions on (001) and (111) surfaces using MD and AFM, G. Gao, R.J. Cannara, R.W. Carpick, and J.A. Harrison, Langmuir, 23 (10), 5394-405 (2007).

Surface composition, bonding, and morphology in the nucleation and growth of ultra-thin, high quality nanocrystalline diamond films, A.V. Sumant, P.U.P.A. Gilbert, D.S. Grierson, A.R. Konicek, M. Abrecht, J.E. Butler, T. Feygelson, S.S. Rotter, R.W. Carpick, Diam. Rel. Mat., 16, 718-24 (2007).

Predictions and observations of transitions in atomic-scale stick-slip friction. S.N. Medyanik, W.K. Liu, I.-H. Sung, R.W. Carpick, Phys. Rev. Lett., 97 (13) 136106/1-4 (2006).

The use of tungsten interlayers to enhance the initial nucleation and conformality of ultrananocrystalline diamond (UNCD) thin films, N.N. Naguib, J.W. Elam, J. Birrell, J. Wang, D.S. Grierson, B. Kabius, J.M. Hiller, A.V. Sumant, R. W. Carpick, O. Auciello, J.A. Carlisle, Chem. Phys. Lett., 430 (4-6) 345-50 (2006).

Lateral force calibration in atomic force microscopy: A new lateral force calibration method and general guidelines for optimization, R.J. Cannara, M. Eglin, R.W. Carpick, Rev. Sci. Instrum., 77 (5), 53701/1-11 (2006).

Mechanical analysis, characterization, and design considerations of vibrations in "beetle"-type scanning probe microscopes, M.J. Brukman, and R.W. Carpick. Rev. Sci. Instrum., 77 (5), 033706/1-7 (2006).

Growth of mechanically fixed and isolated vertically-aligned carbon nanotubes and nanofibers for nanomechanical testing by DC-plasma-enhanced hot filament chemical vapor deposition, H.Y. Yap, B. Ramaker, A.V. Sumant, R.W. Carpick, Diam. Rel. Mater., 15 (10), 1622-1628 (2006).

Nanotribological properties of alkanephosphonic acid self-assembled monolayers on aluminum oxide: Effects of fluorination and substrate crystallinity, M.J. Brukman, G.O. Marco, T.D. Dunbar, L.D. Boardman, and R.W. Carpick, Langmuir, 22(9) 3988-3998 (2006).

Microparticle manipulation using inertial forces, M. Eglin, M.A. Eriksson, and R.W. Carpick, Appl. Phys. Lett., 88 091913/1-3 (2006).

In-situ wear studies of surface micromachined interfaces subject to controlled loading, E.E. Flater, A.D. Corwin, M.P. de Boer, and R.W. Carpick, Wear, 260 (6) 580-593 (2006).

Cantilever tilt compensation for variable-load atomic-force microscopy, R.J. Cannara, M.J. Brukman, and R.W. Carpick, Rev. Sci. Instrum., 76 (5) 53706/1-6 (2005).

Multiscale roughness and modeling of MEMS interfaces, C. K. Bora, E.E. Flater, M.D. Street, J.M. Redmond, M.J. Starr, M.E. Plesha, and R.W. Carpick. Trib. Lett., 19 (1) 37-48 (2005).

Accounting for the JKR-DMT transition in adhesion and friction measurements with AFM, D.S. Grierson, E.E. Flater, and R.W. Carpick, J. Adhes. Sci. Technol., 19 (3-5) 291-311(2005).

Toward the ultimate tribological interface: Surface chemical optimization and nanoscale single asperity properties of ultrananocrystalline diamond, A.V. Sumant, D.S. Grierson, J.E. Gerbi, J. Birrell, U.D. Lanke, O. Auciello, J.A. Carlisle, and R.W. Carpick, Adv. Mat., 17 (8) 1039-1045 (2005).

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Thomas A.V. Cassel
Practice Professor of Mechanical Engineering and Applied Mechanics; Director, Engineering Entrepreneurship Program
Email: tcassel at seas.upenn.edu
Personal Website

Research Interests:
Engineering Entrepreneurship

Selected Recent Publications:
Thomas Cassel. Engineering Entrepreneurship at Penn. Proceedings of the 2003 American Society for Engineering Education Annual Conference & Exposition. 2003.


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Christopher S. Chen
Associate Professor of Bioengineering
Email: chrischen at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Micro- and Nanotechnology; Transduction of mechanical forces by cells; Relationship between cellular and multicellular structure and biological function; Angiogenesis; Cancer; and Stem cell biology. Dr. Chen's laboratory studies how the interactions between cells and their surrounding tissue microenvironment drives their behavior. His group develops novel microfabriaction and nanotechnology-based tools to manipulate and monitor these interactions in order to better understand how cells function in normal and disease contexts.

Selected Recent Publications:
Bhatia, S.N, Chen, C.S. (2007) Special issue on Cell and Tissue Engineering in Microsystems. Lab on a Chip. 7: 666.

Nelson, C.M., Liu, W.F., Chen, C.S. (2007) Manipulation of Cell-Cell Adhesion Using Bowtie-Shaped Microwells. In Methods in Molecular Biology: Adhesion Protein Protocols, 2nd Ed. (ed. A.S. Coutts). Human Press. 270: 1-9.

Alom Ruiz, S., Chen, C.S. (2007) Microcontact printing: a tool to pattern. Soft Matter. 3(2):168-177.

Pirone, D.M., Liu, W.F., Gao, L., Raghavan, S., Lemmon, C.A., Romer, L.H., Chen, C.S. (2006) An Inhibitory Role for FAK in Regulating Proliferation: a Link Between Limited Adhesion and RhoA-ROCK Signaling. J Cell Biol. 174(2):277-88.

Liu, W.F., Nelson, C.M., Pirone, D.M., Chen, C.S. (2006) E-cadherin Engagement Stimulates Proliferation Via Rac1. J Cell Biol. 173(3):431-441.

Sniadecki, N.J., Desai, R.D., Alom Ruiz, S., Chen, C.S. (2006) Nanotechnology for Cell-Substrate Interactions. Annals of Biomed Eng. 34(1):59-74.

Jean, R., Spector, A., Chen, C.S. (2005) Finite-element analysis of the adhesion-cytoskeleton-nucleus mechanotransduction pathway during endothelial cell rounding: axisymmetric model. J Biomech Eng. 127(4):594-600.

Nelson, C.M., Jean, R.P., Tan, J.L., Liu, W.F., Sniadecki, N.J., Spector, A.A., Chen, C.S., (2005) Emergent patterns of growth contolled by multicellular form and mechanics. Proc Nat Acad Sci. 102(33):11594-11599.

Herndon, T.M., Pirone, D.M., Tsokos, G.C., Chen, C.S., (2005) T cell-to-T cell clustering enhances NF-κB activitity by a PI3K signal mediated by Cbl-b and Rho. Biochem Biophys Res Comm. 332:1133-1139.

Tanase, M., Felton, E.J., Gray, D.S., Hultgren, A., Chen, C.S., Reich, D. (2005) Assembly of multicellular constructs and microarrays of cells using magnetic nanowires. Lab on a Chip. 5:598-605.

Lemmon, C.A., Sniadecki, N.J., Ruiz, S.A., Tan, J.T., Romer, L.H., Chen, C.S. (2005) Shear Force at the Cell-Matrix Interface: Enhanced Analysis For Microfabricated Post Array Detectors. Mechanics & Chemistry of Biosystems. 2(1):1-16.

Yim, E.K.F., Reano, R.M., Pang, S.W., Yee, A.F., Chen, C.S., Leong, K.W. (2005) Nanopattern-induced changes in morphology and motility in smooth muscle cells. Biomaterials. 26:54035-5413.

Chen, C.S., Jiang, X., Whitesides, G.M. (2005) Microengineering the Enviroment of Mammalian Cells in Culture. MRS Bulletin. 30:194-201.

Wang, A.Y., Mo, X., Chen, C.S., Yu, S.M., (2005) Facile Modification of Collagen Directed by Collagen Mimetic Peptides. J Am Chem Soc. 127(12):4130-4131

Hultgren, A., Tanase, M., Felton, E.J., Bhadriraju, K., Salem, A.K., Chen, C.S., Reich, D. (2005) Optimization of Yield in Magnetic Cell Separations Using Nickel Nanowires of Different Lengths. Biotech Prog. 21:509-515.

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I-Wei Chen
Professor of Materials Science and Engineering
Email: iweichen at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Complex Oxides: nanograin ferroelectrics, magnetoresistant ruthenates, and resistance memory switching devices. Nanoparticles: functionalized colloids for coating and tissue engineering, molecular imaging using magnetic and fluorescent smart colloids. Ceramics: silicon nitride, sialon and zirconia.


Selected Recent Publications:
H. Choi and I-W. Chen, "Nanometer-sized Carrier Medium," U.S. Patent 7,189,417 (2007).

I-W. Chen and A. Mamchik, "Magnetically and Electrically-Induced Variable Resistance Materials and Method for Preparing Same," U.S. Patent 7,211,199 (2007).

A. M. Lipski et al., "Nanoscale engineering of biomaterial surfaces," Adv Mater 19 (4), 553-557 (2007).

I. Fishbein et al., "Bisphosphonate-mediated gene vector delivery from the metal surfaces ot stents," Proc.Natl.Acad.Sci.U.S.A. 103 (1), 159-164 (2006).

I. Fishbein et al., "Bisphosphonate-mediated gene vector delivery from the metal surfaces of stents," Proc.Natl.Acad.Sci.U.S.A. 103 (1), 159-164 (2006).

S. Jamaluddin et al., "Homocysteine inhibits cyclin a promoter methylation via DNMT3 inactivation in human endothelial cells." Blood 108 (11), 516A-516A (2006). Delete this one--I don't think it is mine.

C. J. Kim and I. W. Chen, "Effect of top electrode on resistance switching of (Pr, Ca)MnO3 thin films," Thin Solid Films 515 (4), 2726-2729 (2006).

S. G. Kim, Y. Wang and I. W. Chen, "Strain relaxation in buried SrRuO3 layer in (Ca1-xSrx)(Zr1-xRux)O-3/SrRuO3," Appl.Phys.Lett. 89 (3), 031905 (2006).

N. Royo et al., "Hippocampal neuroprotection by NT-4," J.Neurotrauma 23 (5), 796-796 (2006). Delete this one, I don't think it is mine.

R. Shuba and I. W. Chen, "Machinable alpha-SiAlON," J Am Ceram Soc 89 (7), 2147-2153 (2006).

Roman Shuba and I-Wei Chen, "The effect of powder mixing procedures on α-SiAlON," J Am Ceram Soc 89 (3), 1110-1113 (2006).

Roman Shuba and I-Wei Chen, "Elimination of grain boundary glass in a-sialon by adding aluminium nitride," J Am Ceram Soc 89 (3), 1065-1071 (2006).

S. Shuba, A. Mamchik and I. W. Chen, "A-site substitution of SrRuO3 using La, K and Pb," Journal of Physics-Condensed Matter 18 (40), 9215-9220 (2006).

R. Shuba and I. W. Chen, "Refractory alpha-SiAlON containing La2O3," J Am Ceram Soc 89 (9), 2860-2868 (2006).

R. Shuiba and I. W. Chen, "Elimination of grain boundary glass in alpha-sialon by adding aluminium nitride," J Am Ceram Soc 89 (3), 1065-1071 (2006).

S. J. Stachelek et al., "Prevention of oxidative degradation of polyurethane by covalent attachment of di-tert-butylphenol residues," J.Biomed.Mater.Res.A. 78 (4), 653-661 (2006).

J. Tatami et al., "Fracture resistance and contact damage of TiN particle reinforced Si3N4 ceramics," Journal of the Ceramic Society of Japan 114 (1335), 1049-1053 (2006).

X. H. Wang, P. L. Chen and I. W. Chen, "Two-step sintering of ceramics with constant grain-size, I. Y2O3," J Am Ceram Soc 89 (2), 431-437 (2006).

X. H. Wang et al., "Two-step sintering of ceramics with constant grain-size, II: BaTiO 3 and Ni-Cu-Zn ferrite," J Am Ceram Soc 89 (2), 438-443 (2006).

Xiao-Hui Wang, Pei-Lin Chen and I-Wei Chen, "Two-step sintering of ceramics with constant grain-size, I. Y 2O3," J Am Ceram Soc 89 (2), 431-437 (2006).

D. R. Durbin et al., "Effects of seating position and appropriate restraint use on the risk of injury to children in motor vehicle crashes," Pediatrics 115 (3), E305-E309 (2005). Delete this one, I don't think it is mine.

B. N. Kim et al., "Rate of creep due to grain-boundary diffusion in polycrystalline solids with grain-size distribution," Philosophical Magazine 85 (20), 2281-2292 (2005).

C. J. Kim and I. W. Chen, "Resistance switching of Al," Japanese Journal of Applied Physics Part 2-Letters & Express Letters 44 (16-19), L525-L527 (2005).

C. J. Kim, B. I. Kim and I. W. Chen, "Dependence of electrode on switching effect of Pr1-xCaxMnO3 thin film," Japanese Journal of Applied Physics Part 1-Regular Papers Short Notes & Review Papers 44 (3), 1260-1261 (2005).

S. A. McGill et al., "Optical evidence for transient photoinduced magnetization in La0.7Ca0.3MnO3," Physical Review B 71 (7), 075117 (2005).

Y. H. Shin et al., "Kinetics of polarization switching in ferroelectrics," Abstracts of Papers of the American Chemical Society 230, U2812-U2813 (2005).

S. J. Stachelek et al., "Cholesterol-derivatized polyurethane: Characterization and endothelial cell adhesion," Journal of Biomedical Materials Research Part a 72A (2), 200-212 (2005).

S. J. Stachelek et al., "Cholesterol-derivatized polyurethane: characterization and endothelial cell adhesion," J.Biomed.Mater.Res.A. 72 (2), 200-212 (2005).

J. C. Sy, I. W. Chen and V. P. Shastri, "Emulsion-based control of electrospun fiber morphology." Abstracts of Papers of the American Chemical Society 227, U353-U353 (2004).



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Russell J. Composto
Graduate Chair of Materials Science and Engineering; Associate Professor of Materials Science and Engineering; Associate Professor of Chemical and Biomolecular Engineering
Email: composto at lrsm.upenn.edu
Personal Website   |   Research Website

Research Interests:
Polymeric coatings are important in the microelectronics, medical, and chemical industries. Whereas many formulations rely on Edisonian principles, our research aims to provide a fundamental understanding of surface and interface properties using a tool-box of complimentary techniques including low-energy forward recoil spectrometry, a technique developed at Penn, neutron reflectivity, atomic force microscopy, and self-consistent mean field models (SCMF). This research provides new opportunities for technologists to optimize material properties by manipulating macromolecules. Molecular Control of Adhesion: Block copolymers designed to have one block anchor to a substrate and the other entangle with matrix chains can greatly improve adhesion. Previous studies have focused on varying matrix chain length and type in order to manipulate interfacial properties such as interfacial excess and adsorbed layer thickness. Using SCMF, the segment-substrate interaction strength can be determined. Future studies will involve variation of block lengths and substrate surface energy, and adhesion. Dynamics of Phase Separating Thin Film Blends: Many industrial coatings involve multi-phase systems. We are studying how films undergoing phase separation are influenced by surface and interface wetting. A comprehensive understanding of thin film kinetics is underway by simultaneously measuring the wetting layer growth, phase morphology below the wetting layer, domain coarsening, and surface roughness. By understanding how phase separation influences wetting, technologists will be able to control film properties including wettability, wear and permeability.

Selected Recent Publications:
Hyun-Joong Chung et al., "Internal phase separation drives dewetting in polymer blend and nanocomposite films," Macromolecules 40 (2), 384-388 (2007).

Ranjan D. Deshmukh and Russell J. Composto, "Surface segregation and formation of silver nanoparticles created in situ in poly(methyl methacrylate) films," Chemistry of Materials 19 (4), 745-754 (2007).

M. H. Lee et al., "Adhesion of MC3T3-E1 cells to RGD peptides of different flanking residues: Detachment strength and correlation with long-term cellular function," Journal of Biomedical Materials Research Part a 81A (1), 150-160 (2007).

M. H. Lee et al., "Adhesion of MC3T3-E1 cells to RGD peptides of different flanking residues: detachment strength and correlation with long-term cellular function," J.Biomed.Mater.Res.A. 81 (1), 150-160 (2007).

A. G. Secchi et al., "RGDS peptides immobilized on titanium alloy stimulate bone cell attachment, differentiation and confer resistance to apoptosis," J.Biomed.Mater.Res.A. , (2007).

V. Antoci et al., "Antibiotic integral to implant surface inhibits bacterial, but not osteoblast colonization." Journal of Bone and Mineral Research 21, S433-S433 (2006).

H. J. Chung, H. Wang and R. J. Composto, "A morphology map based on phase evolution in polymer blend films," Macromolecules 39 (1), 153-161 (2006).

M. H. Lee et al., "Effect of biomaterial surface properties on fibronectin-alpha5beta1 integrin interaction and cellular attachment," Biomaterials 27 (9), 1907-1916 (2006).

D. Miksa et al., "Dextran functionalized surfaces via reductive amination: morphology, wetting, and adhesion," Biomacromolecules 7 (2), 557-564 (2006).

S. J. Stachelek et al., "Prevention of oxidative degradation of polyurethane by covalent attachment of di-tert-butylphenol residues," J.Biomed.Mater.Res.A. 78 (4), 653-661 (2006).

G. K. Toworfe et al., "Initial attachment of osteoblast-like cells on functionalized surfaces coated with calcium phosphate," Bioceramics 18, Pts 1 and 2 309-311, 275-278 (2006).

G. K. Toworfe et al., "Nucleation and growth of calcium phosphate on amine-, carboxyl- and hydroxyl-silane self-assembled monolayers," Biomaterials 27 (4), 631-642 (2006).

C. Xu et al., "Reversible stimuli-responsive nanostructures assembled from amphiphilic block copolymers," Nano Lett. 6 (2), 282-287 (2006).

C. Xu et al., "pH-responsive nanostructures assembled from amphiphilic block copolymers," Macromolecules 39 (18), 6063-6070 (2006).

N. C. Zhou et al., "Phase behavior of polystyrene and poly (styrene-ran-styrene sulfonate) blends," Macromolecules 39 (6), 2373-2379 (2006).

H. J. Chung et al., "Self-regulated structures in nanocomposites by directed nanoparticle assembly," Nano Lett. 5 (10), 1878-1882 (2005).

A. C. Costa et al., "Block copolymer adsorption from a homopolymer melt to an amine-terminated surface," Eur.Phys.J.E.Soft Matter 18 (2), 159-166 (2005).

A. C. Costa et al., "Dewetting and adsorption in homopolymer films containing triblock copolymers: Role of chain architecture and anchoring block molar fraction," J.Adhesion 81 (7-8), 683-698 (2005).

V. Grigoriou et al., "Apoptosis and survival of osteoblast-like cells are regulated by surface attachment," J.Biol.Chem. 280 (3), 1733-1739 (2005).

M. H. Lee et al., "The effect of non-specific interactions on cellular adhesion using model surfaces," Biomaterials 26 (14), 1721-1730 (2005).

M. D. Lefebvre et al., "Effect of sequence distribution on copolymer interfacial activity," Macromolecules 38 (25), 10494-10502 (2005).

M. Ombelli et al., "A quantitative and selective chromatography method for determining coverages of multiple proteins on surfaces," J.Chromatogr.B.Analyt Technol.Biomed.Life.Sci. 826 (1-2), 198-205 (2005).

S. J. Stachelek et al., "Cholesterol-derivatized polyurethane: characterization and endothelial cell adhesion," J.Biomed.Mater.Res.A. 72 (2), 200-212 (2005).

P. Uttayarat et al., "Topographic guidance of endothelial cells on silicone surfaces with micro- to nanogrooves: orientation of actin filaments and focal adhesions," J.Biomed.Mater.Res.A. 75 (3), 668-680 (2005).

H. J. Chung and R. J. Composto, "Breakdown of dynamic scaling in thin film binary liquids undergoing phase separation," Phys.Rev.Lett. 92 (18), 185704 (2004).

R. J. Composto and H. J. Chung, "Mobile nanoparticles in polymer blend films: Wetting and phase separation behavior." Abstracts of Papers of the American Chemical Society 228, U459-U459 (2004).

A. R. El-Ghannam et al., "Model surfaces engineered with nanoscale roughness and RGD tripeptides promote osteoblast activity," J.Biomed.Mater.Res.A. 68 (4), 615-627 (2004).

D. Miksa et al., "Dextran immobilization on silicon oxide substrates: Grafting density and surface properties." Abstracts of Papers of the American Chemical Society 228, U480-U480 (2004).

G. K. Toworfe et al., "Fibronectin adsorption on surface-activated poly(dimethylsiloxane) and its effect on cellular function," J.Biomed.Mater.Res.A. 71 (3), 449-461 (2004).

B. Zhang Newby and R. J. Composto, "Phase-morphology map of polymer-blend thin films confined to narrow strips," Phys.Rev.Lett. 87 (9), 098302 (2001).

E. A. Kaufmann et al., "Initial events at the bioactive glass surface in contact with protein-containing solutions," J.Biomed.Mater.Res. 52 (4), 825-830 (2000).

H. Wang and R. J. Composto, "Hydrodynamic-flow-driven wetting in thin film polymer blends: growth kinetics and morphology," Phys.Rev.E Stat.Phys.Plasmas Fluids Relat.Interdiscip.Topics 61 (2), 1659-1663 (2000).



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John C. Crocker
Associate Professor of Chemical and Biomolecular Engineering and Skirkanich Associate Professor of Innovation in Chemical Engineering
Email: jcrocker at seas.upenn.edu
Personal Website

Research Interests:
Microrheology of biopolymers, recA searching, 3-D microscopy, device biophysics. Dr. Crocker's research seeks to understand the feedback of mechanical force or stress with biochemistry on the cellular and macromolecular scales and to use the results to engineer useful devices for medical and biochemical applications.

Selected Recent Publications:
P. L. Biancaniello et al., "DNA-mediated phase behavior of microsphere suspensions," Langmuir 23 (5), 2688-2693 (2007).

P. L. Biancaniello and J. C. Crocker, "Line optical tweezers instrument for measuring nanoscale interactions and kinetics," Rev.Sci.Instrum. 77 (11), 113702 (2006).

F. J. Byfield et al., "Evidence for the role of cell stiffness in modulation of volume-regulated anion channels," Acta Physiologica 187 (1-2), 285-294 (2006).

M. L. Gardel et al., "Stress-dependent elasticity of composite actin networks as a model for cell behavior," Phys.Rev.Lett. 96 (8), 088102 (2006).

M. L. Gardel et al., "Prestressed F-actin networks cross-linked by hinged filamins replicate mechanical properties of cells," Proc.Natl.Acad.Sci.U.S.A. 103 (6), 1762-1767 (2006).

B. D. Hoffman et al., "The consensus mechanics of cultured mammalian cells," Proc.Natl.Acad.Sci.U.S.A. 103 (27), 10259-10264 (2006).

A. J. Kim, P. L. Biancaniello and J. C. Crocker, "Engineering DNA-mediated colloidal crystallization," Langmuir 22 (5), 1991-2001 (2006).

J. Liu et al., "Microrheology probes length scale dependent rheology," Phys.Rev.Lett. 96 (11), 118104 (2006).

K. M. Van Citters et al., "The role of F-actin and myosin in epithelial cell rheology," Biophys.J. 91 (10), 3946-3956 (2006).

P. L. Biancaniello, A. J. Kim and J. C. Crocker, "Colloidal interactions and self-assembly using DNA hybridization," Phys.Rev.Lett. 94 (5), 058302 (2005).

B. D. Hoffman et al., "Cytoskeletal rheology and forced unfolding of cross-link protein domains," Biophys.J. 88 (1), 493A-493A (2005).

S. S. Kapur et al., "Role of configurational entropy in the thermodynamics of clusters of point defects in crystalline solids," Physical Review B 72 (1), 014119 (2005).

A. J. Kim, V. N. Manoharan and J. C. Crocker, "Swelling-based method for preparing stable, functionalized polymer colloids," J.Am.Chem.Soc. 127 (6), 1592-1593 (2005).

K. A. Miranda et al., "Measuring cytoskeleton mechanics and its relationship to the actin model," Biophys.J. 88 (1), 493A-493A (2005).

M. P. Valignat et al., "Reversible self-assembly and directed assembly of DNA-linked micrometer-sized colloids," Proc.Natl.Acad.Sci.U.S.A. 102 (12), 4225-4229 (2005).

J. C. Crocker, P. Biancaniello and A. J. Kim, "Measuring and modeling weak adhesion between DNA-grafted colloids." Abstracts of Papers of the American Chemical Society 228, U489-U489 (2004).

D. T. Chen et al., "Rheological microscopy: local mechanical properties from microrheology," Phys.Rev.Lett. 90 (10), 108301 (2003).

A. W. Lau et al., "Microrheology, stress fluctuations, and active behavior of living cells," Phys.Rev.Lett. 91 (19), 198101 (2003).

K. Lin et al., "Colloidal interactions in suspensions of rods," Phys.Rev.Lett. 87 (8), 088301 (2001).

R. J. Owen et al., "Measurement of long-range steric repulsions between microspheres due to an adsorbed polymer," Phys.Rev.E.Stat.Nonlin Soft Matter Phys. 64 (1 Pt 1), 011401 (2001).

J. C. Crocker et al., "Two-point microrheology of inhomogeneous soft materials," Phys.Rev.Lett. 85 (4), 888-891 (2000).

Kh Lin et al., "Entropically driven colloidal crystallization on patterned surfaces," Phys.Rev.Lett. 85 (8), 1770-1773 (2000).

E. R. Weeks et al., "Three-dimensional direct imaging of structural relaxation near the colloidal glass transition," Science 287 (5453), 627-631 (2000).



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Kostas Daniilidis
Associate Professor of Computer and Information Science
Email: kostas at cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
Omnidirectional Vision, Tele-immersion, Analysis of Visual Motion.

Selected Recent Publications:
A. Makadia and K. Daniilidis, "Rotation recovery from spherical images without correspondences," IEEE Trans.Pattern Anal.Mach.Intell. 28 (7), 1170-1175 (2006).

Ameesh Makadia and Kostas Daniilidis, in 2005 IEEE International Conference on Robotics and Automation, Anonymous (Institute of Electrical and Electronics Engineers Inc., Piscataway, NJ 08855-1331, United States, Barcelona, Spain, 2005) pp. 3534-3539.

W. C. Yu et al., "Using skew Gabor filter in source signal separation and local spectral orientation analysis," Image Vision Comput. 23 (4), 377-392 (2005).

K. Daniilidis and N. Papanikolopoulos, "Special issue on Panoramic Robots," Ieee Robotics & Automation Magazine 11 (4), 4-5 (2004).

V. Isler et al., "VC-dimension of exterior visibility," IEEE Trans.Pattern Anal.Mach.Intell. 26 (5), 667-671 (2004).



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Susan B. Davidson
Appointments: Weiss Professor of Computer and Information Science; Deputy Dean of the School of Engineering and Applied Science
Email: susan at cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
Information integration, distributed systems, database systems (models, languages, updates, concurrency), workflow systems, bioinformatics.

Selected Recent Publications:
S. Bowers et al., "A model for user-oriented data provenance in pipelined scientific workflows," Provenance and Annotation of Data 4145, 133-147 (2006).

V. P. Braganholo, S. B. Davidson and C. A. Heuser, "PATAXO: A framework to allow updates through XML views," Acm Transactions on Database Systems 31 (3), 839-886 (2006).

S. Cohen, S. Cohen-Boulakia and S. Davidson, "Towards a model of provenance and user views in scientific workflows," Data Integration in the Life Sciences, Proceedings 4075, 264-279 (2006).

S. Cohen-Boulakia et al., "Path-based systems to guide scientists in the maze of biological data sources," J.Bioinform Comput.Biol. 4 (5), 1069-1095 (2006).

S. Cohen-Boulakia, S. Davidson and C. Froidevaux, "A user-centric framework for accessing biological sources and tools," Data Integration in the Life Sciences, Proceedings 3615, 3-18 (2005).

S. B. Davidson, "Sharing biomedical data with impunity and ease," OMICS 7 (1), 11-12 (2003).



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Peter K. Davies
Chairman and Professor of Materials Science and Engineering
Email: davies at lrsm.upenn.edu
Personal Website

Research Interests:
Ceramics for Wireless Communication: Ceramic dielectric resonators have revolutionized microwave-based wireless communication devices by reducing the size and cost of filters and oscillators in systems ranging from cellular phones to global positioning technologies. The goals of our work are to understand what aspects of the chemistry, structure and processing of these materials are critical in realizing an optimized electronic performance, and use these crystal chemical insights to design and prepare new oxides with an improved dielectric performance. Relaxor Ferroelectric Oxides: Relaxor ferroelectric oxides such as lead magnesium niobate have attracted widespread interest for applications in multi-layer capacitors, transducers, electro-optic devices, and thin film memories. The properties of these systems are intimately related to the nano-level ordering of the metal cations in their crystal structures. Using a broad range of probes to explore their local structure, and new processing schemes and chemical substitutents, we have developed methods to control the cation order and modify the ferroelectric properties of these systems. These approaches are being used to develop a new class of ferroelectric and piezoelectric materials. Cation Order in Electronic Oxides: Ordering reactions can be responsible for order of magnitude changes in the conduction, dielectric, and optical properties of oxide systems. We are using a combination of TEM and diffraction probes, and novel low temperature synthesis routes to explore the response of the properties of a series of transition metal oxide systems to variations in their short-, medium-, and long-range cation order.

Selected Recent Publications:
I. Grinberg et al., "Structure and polarization in the high Tc ferroelectric Bi(Zn,Ti)O3-PbTiO3 solid solutions," Phys.Rev.Lett. 98 (10), 107601 (2007).

D. M. Stein, M. R. Suchomel and P. K. Davies, "Enhanced tetragonality in (x)PbTiO3-(1-x)Bi(B ' B '')O-3 systems: Bi(Zn3/4W1," Appl.Phys.Lett. 89 (13), 132907 (2006).

H. Wu and P. K. Davies, "Influence of non-stoichiometry on the structure and properties of Ba(Zn1/3Nb2," J Am Ceram Soc 89 (7), 2271-2278 (2006).

Ilya Grinberg et al., "Predicting morphotropic phase boundary locations and transition temperatures in Pb- and Bi-based perovskite solid solutions from crystal chemical data and first-principles calculations," J.Appl.Phys. 98 (9), 094111 (2005).

M. R. Suchomel and P. K. Davies, "Enhanced tetragonality in (x)PbTiO3-(1-x)Bi(Zn1/2Ti1," Appl.Phys.Lett. 86 (26), 262905 (2005).

M. Thirumal and P. K. Davies, "Ba8ZnTa6O24: A new high Q dielectric perovskite," J Am Ceram Soc 88 (8), 2126-2128 (2005).

P. Juhas, P. K. Davies and M. A. Akbas, "Structure and dielectric properties of Pb(Sc2/3W1/3)O-3-Pb(Zr," J Am Ceram Soc 87 (11), 2086-2092 (2004).

H. Wu and P. K. Davies, "Ordered perovskites in the A(2+) (Li1/4Nb3/4)O-3-A(2+) (Li2/5W3," Journal of Solid State Chemistry 177 (11), 4305-4315 (2004).

P. K. Davies, "High Tc ceramic superconductors: introduction, background, and challenges to the electron microscopist," J.Electron Microsc.Tech. 8 (3), 247-250 (1988).



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Andre' DeHon
Associate Professor in Electrical and Systems Engineering, Associate Professor in Computer Science
Email: andre at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Broadly, I'm interested in understanding and characterizing the computational requirements of tasks (how do we capture the computational resource mix necessary to perform a computation? what's the minimal computational work which really needs to be done to implement a computation?) and systematizing our understanding of how to most efficiently engineer systems which implement computations (how should resources be organized and allocated? how do restrictions upon or regularities in input or task characteristic facilitate more economical implementation?). In more traditional terms, I'm interested in computing
systems spanning from transistors up through applications including computer architecture, VLSI, parallel computation, compilation and mapping technology, operating and run-time systems, and CAD.

I'm most interested in the interrelations of these disciplines and how we best exploit them to build efficient and powerful computing systems. My current research is focussed on spatial, post-fabrication programmable architectures (e.g. reconfigurable computing) as a complement to the more heavily studied sequential, time-sliced computing architectures. In my research, I also try to understand how these architectures fit into the larger design space of computational organizations. One particular loci of study is on-chip interconnect organization and design. Looking beyond our traditional, lithographic processing, I'm also interested in bottom-up, nanoscale computing devices (e.g. molecular electronics). How do we assemble reliable computing devices at this scale? How does this change our cost landscape, abstractions, and ultimately architectures and computations?

Selected Recent Publications:
Nachiket Kapre and André DeHon, "Proceedings of the IEEE Symposium on Computer Arithmetic", pp. 205--213 (Arith18, June 25--27, 2007)

A. DeHon, C. S. Lent and F. Lombardi, "Introduction to the special section on nano systems and computing," IEEE Trans.Comput. 56 (2), 145-146 (2007).

Benjamin Gojman, Raphael Rubin, Concetta Pilotto, Tetsufumi Tanamoto, and André DeHon. 3D Nanowire-Based Programmable Logic. In Proceedings of the International Conference on Nano-Networks (Nanonets2006), September 2006.

Kumiko Numora, Keiko Abe, Shinobu Fujita, and André DeHon. Novel Design of Three-Dimensional Crossbar for Future Network on Chip based on Post-Silicon Devices. In Proceedings of the International Conference on Nano-Networks (Nanonets2006), September 2006.

John E. Savage, Eric Rachlin, André DeHon, Charles M. Lieber, and Yue Wu. Radial Addressing of Nanowires. In ACM Journal on Emerging Technologies in Computing Systems, Volume 2, Number 2, Pages 129--154, April 2006.

André DeHon, Yury Markovsky, Eylon Caspi, Michael Chu, Randy Huang, Stylianos Perissakis, Laura Pozzi, Joseph Yeh, and John Wawrzynek. Stream Computations Organized for Reconfigurable Execution. In Journal of Microprocessors and Microsystems, Volume 30, Number 6, Pages 334--354, September, 2006.

André DeHon, Randy Huang, and John Wawrzynek. Stochastic Spatial Routing for Reconfigurable Networks. In Journal of Microprocessors and Microsystems, Volume 30, Number 6, Pages 301--318, September, 2006.

Michael deLorimier, Nachiket Kapre, Nikil Mehta, Dominic Rizzo, Ian Eslick, Raphael Rubin, Tomas Uribe, Thomas F. Knight, Jr. and André DeHon. GraphStep: A System Architecture for Sparse-Graph Algorithms. In Proceedings of the IEEE Symposium on Field-Programmable Custom Computing Machines, April 2006.

Nachiket Kapre, Nikil Mehta, Michael deLorimier, Raphael Rubin, Henry Barnor, Michael J. Wilson, Michael Wrighton, and André DeHon. Packet-Switched vs. Time-Multiplexed FPGA Overlay Networks. In Proceedings of the IEEE Symposium on Field-Programmable Custom Computing Machines, April 2006.

Michael Wrighton and André DeHon. SAT-Based Optimal Hypergraph Partitioning with Replication. In Proceedings of the Asia and South Pacific Design Automation Conference, January 2006.

André DeHon. Deterministic Addressing of Nanoscale Devices Assembled at Sublithographic Pitches. In IEEE Transactions on Nanotechnology, Volume 4, Number 6, Pages 681--687, Nov. 2005.


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Scott L. Diamond
Arthur E. Humphrey Professor of Chemical and Biomolecular Engineering and Bioengineering; Associate Director and Charter Member of Institute for Medicine and Engineering; Director of Biotechnology Program
Email: sld at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Mechano-biology, blood clotting and blood clot dissolving reactions, pharmacodynamics of thrombolytic therapies, endothelial gene therapy, proteomics of blood. Endothelial Cell Mechanobiology: This research ultilizes molecular and cell biology approches to explore issues related to cardiovascular disease of the arterial system. Our focus is on how physical forces generated by blood flow (hemodynamics) regulate blood vessel wall biology. Vascular surgeons and pathologists have long recognized that atherosclerotic lesions are localized at sites of low and disturbed blood flow. Additionally, physiologists have recognized that the endothelium plays an important role in matching the vessel diameter to the blood flow through vessel. Yet how does an endothelial cell respond to its hemodynamic environment? To date, our investigations have shown that the expression of several genes is altered in complete ways when endothelial cells are exposed to arterial levels of physical forces. We are interested in defining and promoting the hemodynamic regulation of endothelial phenotypes associated with enhanced vasodilatory activity and smooth muscle cell growth antagonism. Thrombosis and Thrombolytics: Thrombolytic therapy is well established in the US as a treatment for acute MI as well as for peripheral arterial and venous thrombosis. Thrombolytic treatment of stroke is in the developmental stage. A goal of our research is the advancement of large scale computations to simulate intravenous, intracoronary, or intrathrombic delivery of a combination of lytic agents to a given clot structure/comoposition for coronary, peripheral artery, and venous thrombolysis. We are conducting experimental and theoretical investigations of blood clotting and blood clot dissolving reactions under realistic hemodynamic conditions. We seek to define the quantitative relationship between the pharmacodynamics of a given thrombolytic therapy, the composition and location of a thrombus, and the consequent reperfusion time and flow rate. Particular attention is placed on the penetration rates of plasma constituents into thrombi (driven by hemodynamic pressures) and the consequent dissolution dynamics. We are advancing the use of computer simulation of the clot dissolving reactions using biphasic, multicomponent convection-dispersion-reaction equations for erodible fibrin structures with heterogeneous adsorption and reaction. Additionally, the design of catheters for local thrombolytics requires accurate understanding of coupled reaction-transport processes. Endothelial Gene Therapy: Gene transfer by nonviral methodologies (e.g. lipofection) are not efficient in cell populations with low mitotic rates. Unfortunately, cells are not actively dividing in many in vivo tissues that are potential clinical targets for gene therapy. While receptor targeting, fusigenic peptides, or endosome disrupting agents help overcome some of the first barriers that limit liposome-based gene delivery, virus free gene transfer using liposomes will have limited clinical utility because of the difficulty of transporting genetic material into the nucleus of a nondividing cell. We propose research to understand and potentially overcome this final rate limit of nuclear entry encounted with lipofection of nondividing cells. We seek to develop methodologies for delivering large genetic packages into the nucleus of nondividing cells. This will be critical for the success of nonviral mediated gene therapy in vivo and various tissue engineering applications where the low mitotic index of target cells would greatly limits the impact of many potential therapies.

Selected Recent Publications:
S. L. Diamond, "Methods for mapping protease specificity," Curr.Opin.Chem.Biol. 11 (1), 46-51 (2007).

J. A. Gruneich and S. L. Diamond, "Synthesis and structure-activity relationships of a series of increasingly hydrophobic cationic steroid lipofection reagents," J.Gene Med. 9 (5), 381-391 (2007).

R. G. Handwerger and S. L. Diamond, "Biotinylated photocleavable polyethylenimine: capture and triggered release of nucleic acids from solid supports," Bioconjug.Chem. 18 (3), 717-723 (2007).

B. R. Murphy et al., "Delivery and mechanistic considerations for the production of knock-in mice by single-stranded oligonucleotide gene targeting," Gene Ther. 14 (4), 304-315 (2007).

K. Ganguly et al., "Fibrin affinity of erythrocyte-coupled tissue-type plasminogen activators endures hemodynamic forces and enhances fibrinolysis in vivo," J.Pharmacol.Exp.Ther. 316 (3), 1130-1136 (2006).

D. N. Gosalia et al., "Functional phenotyping of human plasma using a 361-fluorogenic substrate biosensing microarray," Biotechnol.Bioeng. 94 (6), 1099-1110 (2006).

K. Y. Horiuchi et al., "Microarrays for the functional analysis of the chemical-kinase interactome," Journal of Biomolecular Screening 11 (1), 48-56 (2006).

M. S. Kim and S. L. Diamond, "Controlled release of DNA," Bioorg.Med.Chem.Lett. 16 (21), 5572-5575 (2006).

M. S. Kim and S. L. Diamond, "Controlled release of DNA/polyamine complex by photoirradiation of a solid phase presenting o-nitrobenzyl ether tethered spermine or polyethyleneimine," Bioorg.Med.Chem.Lett. 16 (21), 5572-5575 (2006).

M. S. Kim and S. L. Diamond, "Photocleavage of o-nitrobenzyl ether derivatives for rapid biomedical release applications," Bioorg.Med.Chem.Lett. 16 (15), 4007-4010 (2006).

I. J. Laurenzi, J. D. Bartels and S. L. Diamond, "Regression of multicomponent sticking probabilities using a genetic algorithm," Ind Eng Chem Res 45 (16), 5482-5488 (2006).

U. M. Okorie and S. L. Diamond, "Matrix protein microarrays for spatially and compositionally controlled microspot thrombosis under laminar flow," Biophys.J. 91 (9), 3474-3481 (2006).

K. E. Edmondson, W. S. Denney and S. L. Diamond, "Neutrophil-bead collision assay: pharmacologically induced changes in membrane mechanics regulate the PSGL-1/P-selectin adhesion lifetime," Biophys.J. 89 (5), 3603-3614 (2005).

D. N. Gosalia et al., "High throughput substrate specificity profiling of serine and cysteine proteases using solution-phase fluorogenic peptide microarrays," Mol.Cell.Proteomics 4 (5), 626-636 (2005).

D. N. Gosalia et al., "Profiling serine protease substrate specificity with solution phase fluorogenic peptide microarrays," Proteomics 5 (5), 1292-1298 (2005).

K. Y. Horiuchi et al., "Functional nanoliter chemical microarray for ultra high throughput screening and kinase profiling," Abstracts of Papers of the American Chemical Society 230, U2744-U2745 (2005).

K. Lo, W. S. Denney and S. L. Diamond, "Stochastic modeling of blood coagulation initiation," Pathophysiol.Haemost.Thromb. 34 (2-3), 80-90 (2005).

H. C. Ma et al., "Nanoliter homogenous ultra-high throughput screening microarray for lead discoveries and IC50 profiling," Assay and Drug Development Technologies 3 (2), 177-187 (2005).

A. Price et al., "Targeting viral-mediated transduction to the lung airway epithelium with the anti-inflammatory cationic lipid dexamethasone-spermine," Mol.Ther. 12 (3), 502-509 (2005).

G. Simmons et al., "Inhibitors of cathepsin L prevent severe acute respiratory syndrome coronavirus entry," Proc.Natl.Acad.Sci.U.S.A. 102 (33), 11876-11881 (2005).

G. Simmons et al., "Inhibitors of cathepsin L prevent severe acute respiratory syndrome coronavirus entry," Proc.Natl.Acad.Sci.U.S.A. 102 (33), 11876-11881 (2005).

S. L. Diamond, "High efficiency lipofection and gene correction of mouse embryonic stem cells using nuclear targeting technology." Abstracts of Papers of the American Chemical Society 227, U206-U206 (2004).

D. M. Eckmann and S. L. Diamond, "Surfactants attenuate gas embolism-induced thrombin production," Anesthesiology 100 (1), 77-84 (2004).

D. N. Gosalia, C. M. Salisbury and S. L. Diamond, "Profiling serine protease substrate specificity with solution phase peptide microarrays." Abstracts of Papers of the American Chemical Society 227, U204-U204 (2004).

J. A. Gruneich et al., "Cationic corticosteroid for nonviral gene delivery," Gene Ther. 11 (8), 668-674 (2004).

J. Y. Ji and S. L. Diamond, "Exogenous nitric oxide activates the endothelial glucocorticoid receptor," Biochem.Biophys.Res.Commun. 318 (1), 192-197 (2004).

K. E. Kadash, M. B. Lawrence and S. L. Diamond, "Neutrophil string formation: hydrodynamic thresholding and cellular deformation during cell collisions," Biophys.J. 86 (6), 4030-4039 (2004).

K. Lo and S. L. Diamond, "Blood coagulation kinetics: high throughput method for real-time reaction monitoring," Thromb.Haemost. 92 (4), 874-882 (2004).

H. Ma et al., "Mouse embryonic stem cells efficiently lipofected with nuclear localization peptide result in a high yield of chimeric mice and retain germline transmission potency," Methods 33 (2), 113-120 (2004).

Goel MS, Diamond SL.Factor VIIa-mediated tenase function on activated platelets under flow. J Thromb Haemost. 2004 Aug;2(8):1402-10.

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Dennis E. Discher
Professor of Chemical and Biomolecular Engineering, Bioengineering, and Mechanical Engineering and Applied Mechanics; Physics and Cell & Molecular Biology Graduate Groups; Adjunct Professor, Structural Biology – The Wistar Institute; Member, Institute of Medicine and Engineering,Graduate Group Chair, Chemical and Biomolecular Engineering.
Email: discher at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Stem Cells and Nano/BioMolecular Science & Engineering are our main areas of interest. We pursue and exploit deeper understanding of protein & polymers aspects of membranes and soft interfaces within and across the fields of systems biophysics and materials. Systems and Processes of direct interest include: protein folding and flexibility, cell deformability and immunocompatability, block copolymer vesicles (Polymersomes) and worm-like micelles (Filomicelles) for drug delivery, physical determinants of stem cell and myocyte differentiation and disease, and nuclear envelope-chromatin interactions in isolated nuclei. Methods used range from molecular biology and single molecule AFM to micro-patterning and fluorescence ultra-microscopy. Modeling efforts range from pathway kinetics and continuum mechanics to computation intensive Monte Carlo and Molecular Dynamics.

Selected Recent Publications:
C.P. Johnson, H-Y. Tang, C. Carag, D.W. Speicher, and D.E. Discher. Forced unfolding of proteins within cells. Science (Aug.3, 2007).

Y. Geng, P. Dalhaimer, S. Cai, R. Tsai, M. Tewari, T. Minko, and D.E. Discher. Shape effects of filaments versus spherical particles in flow and drug delivery. Nature Nanotechnology 2: 249-255 (2007).

P. Dalhaimer, D.E. Discher*, T. Lubensky. Crosslinked actin networks exhibit liquid crystal elastomer behavior, including soft-mode elasticity. Nature Physics 3: 354-360 (2007) (*corresponding author).

Engler, S. Sen, H.L. Sweeney, and D.E. Discher. Matrix elasticity directs stem cell lineage specification. Cell 126: 677-689 (2006).

F. Ahmed, R. Pakunlu, G. Srinivas, A. Brannon, F.S. Bates, M.L. Klein, T. Minko, and D.E. Discher. Shrinkage of a rapidly growing tumor by drug-loaded polymersomes: pH-triggered release through copolymer degradation. ACS - Molecular Pharmaceutics 3: 340-350 (2006).

D.E. Discher*, P. Janmey, Y-L. Wang. Tissue cells feel and respond to the stiffness of their substrate. Science 310: 1139-1143 (2005). (*corresponding author).

Y. Geng and D.E. Discher. Hydrolytic shortening of polycaprolactone-block-(polyethylene oxide) worm micelles. JACS - Journal of the American Chemical Society 127: 12780-12781 (2005).

V. Ortiz, S. Nielsen, M.L. Klein, and D.E. Discher. Unfolding a linker between helical repeats. Journal of Molecular Biology 349: 638-647 (2005).

A. Engler, M. Sheehan, S. Sen, C. Bonnemann, H.L. Sweeney, and D.E. Discher. Myotubes differentiate optimally on substrates with tissue-like stiffness: Pathological implications of stiff or soft microenvironments. Journal of Cell Biology 166(6): 877-887 (2004). ** With accompanying Editor's Highlight. And Highlight in Nature **

D.E. Discher* and A. Eisenberg. Polymer Vesicles. (invited Review) Science 297: 967-973 (2002). Cover Article (*corresponding author).

P. Carl, C. Kwok, G. Manderson, D.W. Speicher, and D.E. Discher. Forced unfolding modulated by disulfide bonds in the immunoglobulin domains of a cell adhesion molecule. PNAS (Proceedings of the National Academy of Science – USA) 98: 1565-1570 (2001).

H. Aranda-Espinoza, H. Bermudez, F.S. Bates, and D.E. Discher. Electromechanical limits of polymersomes. Physical Review Letters 87: 208301/pg.1-4 (2001).

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Paul Ducheyne
Professor of Bioengineering; Professor of Orthopaedic Surgery Research; Member of the Institute for Medicine and Engineering; Director of Center for Bioactive Materials and Tissue Engineering
Email: ducheyne at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Since the late 1980's when the challenge of in vitro synthesis of bone tissue was first addressed, the investigation of mechanistic effects of materials on cellular functions, specifically cell attachment, proliferation, differentiation and extracellular matrix formation, have been central to this lab's activities. Analyses deal extensively with the interface zone between materials and cells and tissues, using both materials science techniques as well as life science methods. In addition, studies focus on the combined effects of microgravity and substrate material on cellular functions; the use of self assembled monolayer chemistry to create highly controlled surfaces; studying the effect of calcification of such surfaces on cell function; and the controlled release of growth factors, cytokines, antibiotics, etc.... from bioactive, silica based sol gels.

Selected Recent Publications:
M. H. Lee et al., "Adhesion of MC3T3-E1 cells to RGD peptides of different flanking residues: Detachment strength and correlation with long-term cellular function," Journal of Biomedical Materials Research Part a 81A (1), 150-160 (2007).

S. Radin and P. Ducheyne, "Controlled release of vancomycin from thin sol-gel films on titanium alloy fracture plate material," Biomaterials 28 (9), 1721-1729 (2007).

A. G. Secchi et al., "RGDS peptides immobilized on titanium alloy stimulate bone cell attachment, differentiation and confer resistance to apoptosis," J.Biomed.Mater.Res.A. , (2007).

G. A. Silva et al., "The effect of starch and starch-bioactive glass composite microparticles on the adhesion and expression of the osteoblastic phenotype of a bone cell line," Biomaterials 28 (2), 326-334 (2007).

V. Antoci et al., "Antibiotic integral to implant surface inhibits bacterial, but not osteoblast colonization." Journal of Bone and Mineral Research 21, S433-S433 (2006).

M. H. Lee et al., "Effect of biomaterial surface properties on fibronectin-alpha(5)beta(1) integrin interaction and cellular attachment," Biomaterials 27 (9), 1907-1916 (2006).

S. Radin, J. Parvizi and P. Ducheyne, "Thin sol-gel films on fracture fixation material for the controlled release of antibiotics," Bioceramics 18, Pts 1 and 2 309-311, 759-762 (2006).

G. A. Silva et al., "Starch-based microparticles as a novel strategy for tissue engineering applications," Bioceramics 18, Pts 1 and 2 309-311, 907-910 (2006).

G. K. Toworfe et al., "Initial attachment of osteoblast-like cells on functionalized surfaces coated with calcium phosphate," Bioceramics 18, Pts 1 and 2 309-311, 275-278 (2006).

G. K. Toworfe et al., "Nucleation and growth of calcium phosphate on amine-, carboxyl- and hydroxyl-silane self-assembled monolayers," Biomaterials 27 (4), 631-642 (2006).

J. Yao, S. R. Turteltaub and P. Ducheyne, "A three-dimensional nonlinear finite element analysis of the mechanical behavior of tissue engineered intervertebral discs under complex loads," Biomaterials 27 (3), 377-387 (2006).

V. Grigoriou et al., "Apoptosis and survival of osteoblast-like cells are regulated by surface attachment," J.Biol.Chem. 280 (3), 1733-1739 (2005).

W. Lai et al., "Excretion of resorption products from bioactive glass implanted in rabbit muscle," Journal of Biomedical Materials Research Part a 75A (2), 398-407 (2005).

M. H. Lee et al., "The effect of non-specific interactions on cellular adhesion using model surfaces," Biomaterials 26 (14), 1721-1730 (2005).

S. Radin et al., "In vivo tissue response to resorbable silica xerogels as controlled-release materials," Biomaterials 26 (9), 1043-1052 (2005).

S. Radin et al., "Osteogenic effects of bioactive glass on bone marrow stromal cells," Journal of Biomedical Materials Research Part a 73A (1), 21-29 (2005).

J. Yao et al., "The effect of bioactive glass content on synthesis and bioactivity of composite poly (lactic-co-glycolic acid)," Biomaterials 26 (14), 1935-1943 (2005).

J. Yao et al., "Solution-mediated effect of bioactive glass in poly (lactic-co-glycolic acid)-bioactive glass composites on osteogenesis of marrow stromal cells," Journal of Biomedical Materials Research Part a 75A (4), 794-801 (2005).

J. Yao et al., "The effect of bioactive glass content on synthesis and bioactivity of composite poly (lactic-co-glycolic acid)/bioactive glass substrate for tissue engineering," Biomaterials 26 (14), 1935-1943 (2005).

A. R. El-Ghannam et al., "Model surfaces engineered with nanoscale roughness and RGD tripeptides promote osteoblast activity," J.Biomed.Mater.Res.A. 68 (4), 615-627 (2004).

G. K. Toworfe et al., "Fibronectin adsorption on surface-activated poly(dimethylsiloxane) and its effect on cellular function," J.Biomed.Mater.Res.A. 71 (3), 449-461 (2004).

J. C. Gan et al., "Intervertebral disc tissue engineering II: cultures of nucleus pulposus cells," Clin.Orthop.Relat.Res. (411) (411), 315-324 (2003).

T. Livingston, P. Ducheyne and J. Garino, "In vivo evaluation of a bioactive scaffold for bone tissue engineering," J.Biomed.Mater.Res. 62 (1), 1-13 (2002).

Q. Q. Qiu, P. Ducheyne and P. S. Ayyaswamy, "Bioactive, degradable composite microspheres: effect of filler material on surface reactivity,