Beyond Boundaries
Research at Penn Engineering is constantly pushing back the frontiers of science and using innovative methods of thinking to approach problems and find solutions across many fields. If it hasn’t yet been solved, chances are someone at Penn Engineering is working to come up with the solution. Read on to see how our research is reinventing science and technology and creating opportunities to improve the world in which we live.
Cloaking Devices: Not Just for Science Fiction
The closest most of us come to knowing about a cloaking device is Harry Potter’s “invisibility cloak.” Here at 
Penn Engineering, a cloaking device technology has been devised by Nader Engheta, the H. Nedwill Ramsey Professor in the departments of electrical and systems engineering and bioengineering. By combining advances in the use of metamaterials (materials that gain their properties from structure rather than composition) with the science of plasmonics (the study of optical and electrical properties of solid matter), Engheta has theorized a method to make real cloaking devices. This is done by embedding nanoparticles of metals like gold and silver into the surface of a composite host media, creating a displacement current around the surface of an object that is able to bend or absorb specific wavelengths of light, rendering the object invisible at that wavelength. Future applications of this technology include shielding objects from infrared and radar detection.
Interested in learning more? Read on…
Growing Past Cartilage Damage
At the collaborative interface between tissue engineering and 
clinical medicine, research done at Penn Engineering has developed a novel way to allow patients to regrow cartilage in their own bodies, directly in the site where it has been damaged either through injury or disease. Jason Burdick, assistant professor in the department of bioengineering, has invented a way to combine a patient’s own cells with an engineered photopolymerizable biomaterial (a hydrogel) that, when treated with UV light, acts as a scaffold for new tissue formation. The hydrogel gradually breaks down leaving only new healthy cartilage in its place. Unlike current grafting and repair technologies, these biomaterials don’t cause an immune response, so there is no risk of host rejection. Overcoming this cause of chronic pain through the engineering of new materials will no doubt improve the lives of many, especially in the light of additional applications being investigated for the future, such as organ and nerve tissue repair.
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Creating Novel Polymers for Fuel Cells
Hybrid cars are not an uncommon sight in today’s times. But, some in industry claim that electric cars, which 
use fuel cells that harness electricity from chemical reactions, will phase out the need for gasoline in automobiles altogether. Karen Winey, professor in the departments of materials science and engineering and chemical and biomolecular engineering, is working to create technology for an efficient, low-temperature fuel cell by creating better polymers using nanotechnology. These polymers are a special group known as ion-containing polymers or ionomers, which carry the ability to conduct an electrical charge across their surfaces. Although these ionomers are already used to conduct electricity generated by the reactions in a fuel cell, Winey is the head of the first group to use scanning transmission electron microscopy to image the placement and conductivity of the electrons in existing ionomers. The results of this research are then used to map out a combination of the ionomers with carbon nanotubes, which are stronger than steel and conduct electrical current better than copper, to create even more efficient ionomers for fuel cell membranes. This will allow for cleaner and greener automobiles and fuel cells with longer lives.
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In Search of Disease: Improved Medical Imaging
Diseases, such as cancer, are often diagnosed using imaging scans that harness technology like Magnetic 
Resonance (MR) imaging. However, these technologies currently require large amounts of imaging agents and are not efficient at finding disease sites at very early stages, due to reliance on the size of a disease site being large enough to be visible in current scans. By combining nanotechnology with recent discoveries in the molecular and chemical properties of cell growth in disease, Andrew Tsourkas, assistant professor in the departments of bioengineering and radiology, is creating novel imaging agents that will detect disease at its very early stages. By harnessing technology to “tag” an altered molecular profile associated with diseased cells, new formulations of iron oxide- and gadolinium-based nanoparticles are attracted to a disease site and show up in scans at the time of early molecular changes in cells, rather than needing larger groups of diseased cells to form as we do today. This is a major advancement over current technologies, facilitating early detection and the increasingly effective treatment of diseases.
Interested in learning more? Read on…
The Atomic Nature of Friction
In the end, friction wins. It grinds gears, steals energy, and makes temperatures soar. But now a Penn 
Engineering research team is fighting back against this industrial enemy by examining how friction operates, not between pistons and valves, but at the atomic scale. Dr. Robert Carpick, associate professor in the department of mechanical engineering and applied mechanics, has discovered that friction can be reduced by changing the mass of atoms on a material’s surface. Using atomic-force microscopy, diamond and silicon surfaces coated with different single-atom absorbates that vary the atomic mass of a surface but not its chemistry were imaged and analyzed. Findings showed that the larger the mass of surface atoms, the less energy lost to friction and heat. The next step: designing new low-friction surfaces to enhance mechanical efficiency in future devices.
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Healing Patients Through Robotics
Haptics, or the feeling of a surface through robotics technology, has many applications. For example, the 
virtual “click” of the newest Blackberry is a simple application of haptics, since users feel a button clicking that exists only in a virtual realm. In medical robotics, haptics allows surgeons to “feel” tissues and anatomy, even though they are controlling surgical robotic arms instead of being in direct contact with the patient. Research in haptic robotics, led by Katherine Kuchenbecker, the Skirkanich Assistant Professor of Innovation in Mechanical Engineering and Applied Mechanics, is enhancing and improving upon the function of current medical robots. Via a quantitative focus on human experience and a dynamics-based approach to improving the feel of haptic rendering, this next generation of surgical robots will increase surgical accuracy, allow for less invasive procedures, and ultimately result in a better surgical outcome and shorter recovery period for patients.
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Checking the “Reflexes” of Cells
Research done at Penn Engineering has shown that by “tapping” a cell in a way very similar to a doctor 
tapping a patient’s knee with a mallet, a remote response is generated from that cell’s internal machinery. This research, led by Chris Chen, the Skirkanich Professor of Innovation in Bioengineering, builds upon his pioneering adaptation of technology from the semi-conductor industry to reveal new biological insights. Because of his feeling that most barriers to scientific discovery are solved through the development of new techniques, he focuses on the development of new tools and methods to reveal a wide range of biological and mechanical interactions occurring at the cellular level. To continue his research of cell reflexes, he will look to compare the reflex responses of healthy cells to those of the responses from diseased cells, ultimately allowing for the development of new drug therapies and methods for modifying cell to cell interactions.
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SWARMing to the Rescue
At the intersection of artificial intelligence, control theory, robotics, systems engineering and biology, you’ll 
find researchers at Penn Engineering’s GRASP lab working to understand swarming behaviors found in nature (like flocks of birds or schools of fish) so that they can apply biologically-inspired models of swarm behaviors to large networked groups of autonomous vehicles. By developing a framework and methodology for swarming behaviors, Penn Engineering researchers hope to discover if autonomously functioning vehicles can be deployed in the form of a swarm and conduct a mission and respond to commands as a group. This research will enhance the future of military and defense technologies, allowing for an increased use of unmanned vehicles to conduct surveillance and intelligence missions, lessening human casualties on the battlefield.
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It’s The Network: Behavior and Consensus Building
By investigating the political, social and economic struggle between individual self-interest and the need to 
build a consensus, Michael Kearns, professor in the Department of Computer and Information Science, has learned that, depending on the structure of the network of participants, the group’s ability and efficiency in reaching a consensus will change. For example, depending solely on the ability of individuals to interact in a network, as well as the number of connections they have to other participants and other structural properties, there are networks that generate the global adoption of minority viewpoints. In addition, the team demonstrated that individuals with extreme behaviors or a greater awareness of the incentives of others may actually improve the collective performance of the group. It was found that the more aware participants were of the opposing preferences held by their neighbors, the more likely they were to reach a global consensus. Put simply, stubbornness or extremism may pay off when it comes to social welfare. An example of future applications of this research includes organizing a sales team in such a way to gain consensus more quickly.