Single cell analysis on microfluidic devices.

There is significant variability among cells of the same type at the single cell level. This variability may be because of external stimuli that vary temporally or spatially among a population of cells. It may also be owing to the nonsynchronized responses of cells to various stimuli. In addition, differences in otherwise similar cells may be generated by genetic mutations acquired by one or more of the cells. Often times multiple biochemical pathways and molecules are involved in such differences. In order to better understand these differences and to detect those rare cells in a large population that may be indicative of early disease states, methods that are capable of rapidly quantifying multiple molecular species in single cells are desired. Microfluidic devices may provide the optimal platform upon which to develop such methods. Microfluidics has the capability of combining the high-throughput manipulation and transport of cells with rapid, high-efficiency separations and high-sensitivity detection. This chapter describes how to fabricate microfluidic devices for the high-throughput manipulation and rapid electrical lysis of single, nonadherent (suspension) cells followed by the injection and separation of the fluorescently labeled cell contents.