| Microfluidics, a technology based on interconnecting micron-dimension channels, has become popular in chemistry and biology because of its potential for the development of highly integrated “micro total analysis systems” (μTAS). A goal of this work has been to develop μTAS methods for analysis of the contents and behavior of individual biological cells. A second goal has been the development of means to overcome the problem of cell adhesion to microfluidic channel walls. A final goal has been the development of microfluidic flow cells for use with surface plasmon resonance (SPR).; The technique of “chemical cytometry,” or the separation of the contents of a single cell, has been adapted to a μTAS format. Devices formed from glass and poly(dimethylsiloxane) (PDMS) are used to facilitate a highly integrated methodology requiring: (1) isolation of individual cells from a bulk suspension, (2) lysis and fluorescent derivatization of cell contents, and (3) separation of derivatized contents. Preliminary results are reported, and practical impediments to the full implementation of this method are discussed.; The technique of monitoring cellular behavior with microscopy has been adapted to a μTAS format using PDMS devices with integrated valves and pumps. A cell is passively separated from a bulk suspension, followed by delivery of sub-nanoliter volumes of reagents to the selected cell. Various applications are demonstrated, including cell viability assays, ionophore-mediated intracellular calcium ion ([Ca2+]i) measurements, and multistep receptor-mediated [Ca2+]i measurements.; The use of a polyacrylamide coating is explored as a means to prevent cell adhesion onto microfluidic channel walls. Unlike conventional coatings, this technique is spatially programmable such that some channels can be coated while others are unmodified. Cell manipulation without adhesion in coated microfluidic channels is demonstrated.; A new method is reported for fabricating PDMS microfluidic flow cells using a master formed from a conventional positive photoresist. The utility of these devices is demonstrated for use with solution manipulation by means of electroosmotic flow (EOF) and application to surface plasmon resonance (SPR) analysis of sequential protein binding. The results obtained are comparable to macroscale experiments but with significant improvements in reagent consumption. |
