Chapter 7: Applications of Dielectrophoresis in Microfluidics

Microfluidics has revolutionised the manner in which many assessments are carried out. Miniaturisation offers attractive advantages over traditional bench-scale techniques: only small quantities of samples and reagents are required, higher resolution and sensitivity, improved level of integration, lower cost and much shorter processing times. Electrokinetic (EK) techniques have proved to be efficient and robust platforms able to perform complex manipulation of bioparticles for a wide variety of applications. Dielectrophoresis (DEP) is an increasingly popular EK technique successfully used in many studies, as demonstrated by more than 300 papers published every year since 2008. DEP is an EK transport mechanism caused by polarisation effects when a dielectric particle is exposed to a nonuniform electric field. DEP offers great flexibility and several operation modes. The present chapter presents the basic theory of EK and DEP covering the fundamentals of electrode-based DEP and insulator-based DEP; followed by strategically selected examples of DEP studies in the areas of nanoanalytical, bioanalytical and biomedical applications. It is expected that DEP will continue to grow at a fast pace as one of the leading microfluidics techniques for the analysis of biological samples.