ABSTRACT
The ability to obtain precise information from the particles traveling through a cytometer requires adequate focus of the sample stream. This chapter reviews several approaches to achieving focused sample introduction in a manner that may be suitable for the microflow channels associated with flow cytometers. The fabrication of these channels shares fabrication techniques based on two-dimensional networks in microelectronics. Appropriate design, characterization of surface properties, and optimization of channel geometry that enhances stable sheath flow is discussed. Hydrodynamic focusing is one the most popular tools for any microfluidic cytometer due to its ability to align particles for interrogation in a simple and adaptable way. Microfluidic systems will expand the potential applications of flow cytometry in terms of high throughput, volume efficiency, and low cost, and will offer the opportunity to develop new analytical methods. The rapid growth of the microfluidic device technology has pushed the cytometer forward in terms of both miniaturization and reduction of manufacturing costs.
