Biomedical Microfluidics and Electrokinetics
Flow phenomena are of great importance in the study of biological systems: both natural organisms and biomedical devices. Although scientists and engineers have an excellent understanding of transport processes at large length scales, the study of transport processes at cellular length scales and smaller is just beginning. Considering the importance of biological activities at and below the cellular level (see also this volume, Part III, chapter 2.1, by Huang, Sultan, and Ingber), it is critical to understand the microfluidic environment in which these processes occur and how we can manipulate them. Recent strides in micrometer- and nanometer-scale diagnostic techniques have allowed exploration of flow phenomena at length scales comparable to single cells, and even smaller. One of the most useful means of manipulating fluids and suspended species such as cells, DNA, and viruses is with electric fields. Electrokinetic phenomena are important at micron length scales, and can be used to manipulate fluid and particle motion in microfluidic devices. This chapter will briefly review the various methods of electrokinetic fluid and particle manipulation, then review the recently developed microfluidic diagnostic processes available for assessing flow behavior at micron length scales, and finally discuss in detail advances in electrothermal and dielectrophoretic fluid and particle manipulation.
KeywordsMicrofluidic Device Joule Heating Debye Length Nonuniform Electric Field Stern Layer
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