Selected for the May 2005 issue of Virtual Journal of Biological Physics Research

We developed a method to simultaneously perform 3D optical sectioning and optical micromanipulation using a single microscope objective. We combined a multi-trap optical tweezers with a fluorescence microscope, and performed axial scanning of living cells while maintaining a 3D configuration of trapped beads at fixed positions near the cell membrane. This was achieved by compensating the axial movement of the objective by shaping the wave front of the trapping beam with suitable diffractive optical elements displayed on a computer controlled spatial light modulator. Our method has been validated in three different experimental configurations. In the first, we decoupled the position of a trapping plane from the axial movements of the objective and perform optical sectioning of a circle of beads arranged on a fixed plane. In a second experiment, we extended the method to living cell microscopy by showing that mechanical constraints can be applied on the dorsal surface of a cell while performing its fluorescence optical sectioning. In the third experiment, we trapped beads in a three dimensional geometry and performed an axial scan of the volume delimited by the beads.

V. Emiliani, D. Cojoc, E. Ferrari, V. Garbin, C. Durieux, M. Coppey-Moisan, E. Di Fabrizio, Optics Express 13, 1395 (2005)