ABSTRACT
The development of micron-sized components that can perform analytical operations including separation and isolation of specific living cell types is one of the major aims of current research in system integration of biological assays (Anderson et al., 1999; Burns et al., 1998; Burke et al., 1997; Cheng et al., 1996, 1998a; Harrison et al., 1993; He et al., 1999; Kricka, 1998a; Northrup et al., 1998; Schmalzing et al., 1997; Waters et al., 1998; Wilding et al., 1998). Microchips containing microfabricated silicon filters have been developed and shown to be effective for isolation of white blood cells (Wilding et al., 1998). The objective of this chapter is to provide the most recent results in the field of cell separation using microfilter-based devices. It is anticipated that future modifications in size and geometry of the filters will permit precise selection of different-sized cells while further development should increase cell isolation yields. Finally, selection and isolation of rare cell types such as fetal cells in maternal peripheral blood, as well as cancer cells, may be possible using specific capture agents included within microfilterbased chips. Alternative microchip-based methods in which mechanical separation is replaced with an electronically driven system will also be illustrated (Cheng et al., 1998b,c; Hughes et al., 1998; Pethig and Markx, 1997; Stephens et al., 1996; Yang et al., 1999).
