| The reductionist, in-vitro approach to analyzing complex biological processes is greatly advanced by the emergence of microfluidic devices. Microfluidic devices provide a unique and convenient environment in which complex biological process may be studied. In this research, the fluid dynamics of recirculating flows in microvortices is characterized by novel flow mapping and particle tracking methods. This knowledge is then applied to the study of living cells in microfluidic channels. We characterized physical effects of rotation on cells, applied microfluidics to the study of the most virulent form of Malaria, and studied the use of lasers to perform microsurgery on single-cells to extract organelle. Fluid velocities were measured up to ∼47 m/s with the flow-mapping technique. The rotation of optically trapped microparticles was tracked up to as fast as 100Hz with the direct method of manipulating trapped particles. In spinning cells, several phenomena were recorded including nuclear deformation, cell membrane molecule shearing, and organelle displacement during rotation. We characterized the dependence of capillary blockage in malaria on the stage of infection and found that late-stage Schizont cells block channels most effectively while early ring-stage cells act very similarly to normal cells. Furthermore, in-vitro pitting of an infected cell in a 2mum channel and passage of a normal cell through a blocked 6mum capillary was observed. Finally, ultraviolet (UV) and infrared (IR) laser light was used to manipulate and extract single organelle, such as lysosomes and mitochondria, from living cells and the viability of the cells post-surgery was observed. The technique was further improved by the use of an optical vortex trap that limited photobleaching effects and improved organelle viability after surgery. |
