A hybrid electrokinetic bioprocessor for static and dynamic pathogen manipulation in physiological samples

This paper reports a hybrid electrokinetic bioprocessor for label-free manipulation of bacterial pathogens in physiological samples toward lab-on-a-chip applications. While most electrokinetic techniques only function effectively in low-conductivity buffers, hybrid electrokinetics enables operation in high-conductivity samples (~1 S/m). We tackle the major technical hurdle of electrode instability using a Ti-Au-Ti sandwich configuration for manipulating high conductivity samples. The technique combines short-range electrophoresis and dielectrophoresis, and long-range AC electrothermal flow to dramatically improve its effectiveness. The device is the first AC electrokinetic static/dynamic concentrator that can work directly with physiological fluids, such as urine and buffy coats. We show that uropathogenic bacteria and biowarfare agents can be concentrated for over 3 orders of magnitude.