(8c) Bioparticle Capture in a Sawtooth Dielectrophoretic Microchannel

Rapid bioparticle characterization, as a research goal, has fueled a significant and wide-ranging body of work. Much has been accomplished, but new techniques and applications continue to emerge. Innovations in this field may soon enable the development of rapid, on-site bioanalysis devices that improve the availability, accuracy, and scope of clinical diagnosis. Microfluidic electrokinetic approaches provide unique advantages, including short analysis times, microliter sample and reagent volumes, potentially low cost, and portability. The work presented here explores the use of a single, continuous microchannel in which opposing electrokinetic and dielectrophoretic forces create multiple and distinct bioparticle traps. Specifically, it focuses on capture of bioparticles using DC insulator-based dielectrophoresis in a converging, sawtooth-patterned microchannel. The channel design enables localized isolation and concentration of specific particles based on differences in their physical properties. Various targets with disparate characteristics have been captured and concentrated within the device, including human blood cells and mature amyloid protein fibrils. In each case, reproducible capture occurred at specific locales within the sawtooth channel. Differentiable capture of three live Escherichia coli serotypes has also been demonstrated, indicating the potential this technique holds for diagnostic applications.