Non-invasive manipulation of single micro- and nano-sized particles is an important tool for basic biological research. It allows cells, cellular components, and synthetic marker particles treated with biochemical tags to be collected, separated, concentrated, and transported without damage to the objects themselves. Among various non-invasive manipulation mechanisms, a desirable one is the ability to control the orientation of the biological cells, in addition to trapping and moving them. Such capability opens the door to building structured biomaterials for potential applications in constructing biofilms and human tissue engineering. In this proposal, we propose a new approach for optical manipulation and rotation of biological cells that utilizes polarization of light. In addition to flexible manipulation by scanning of the optical beam, the proposed approach is expected to achieve fine orientation control and low optical-intensity requirement compared to conventional optical tweezers. One critical element in the proposed system is the polarization controller. Therefore, in addition to proof-of-concept demonstration for the proposed method, we also plan to fabricate a micro-polarization controller by MEMS (Micro-electro-mechanical system) technology as the first step towards micro-instrumentation. The micro-polarization controller is expected to achieve micro-second response time and occupies substantially smaller volume compared to commercial polarization controllers. In the proposed two-year R21 program, we expect to achieve the following specific aims: 1) Modeling and simulation for the proposed optical micro-manipulator and micro-rotator with biological cells. 2) Proof-of concept demonstration of the proposed approach with asymmetrical micro/nano particles. 3) Design, fabrication, and testing of the MEMS polarization controller. The success of the proposed program will lead to a continuing research program, where the final system for optical manipulation and rotation will be built, and specific biological applications, such as tissue engineering, will be studied. ? ? ?
