Integration of optoelectronic array devices for cell transport and sorting

Current biochip technologies typically rely on electrostatic or mechanical forces for the transport and sorting of biological samples such as single cells. In this paper we have investigated how optical pressure forces can be effectively used for the manipulation of cells and switching in a microfluidic system. By projecting the optical beams externally non-contact between the control devices and the sample chip is possible thus allowing the sample chips to be disposable which reduces the chance of cross-contamination. In one implementation we have shown that vertical cavity surface emitting laser (VCSEL) array devices used as parallel optical tweezer arrays can increase the parallelism of sample manipulation on a chip. We have demonstrated the use of a high-order Laguerre-Gaussian mode VCSEL for optical tweezing of polystyrene microspheres and live cells. We have also shown that optical pressure forces from higher- power sources can be used for the switching of particles within microfluidic channels. Both the attractive gradient force and the scattering force of a focused optical beam have been used to direct small particles flowing through junctions molded in PDMS. We believe that by integrating optical array devices for simultaneous detection and manipulation, highly parallel and low-cost analysis and sorting devices may be achieved.