Short Communication: Ultralow Voltage Electrokinetic Particle Trapping in DC-iEK Devices Using 9 V Alkaline Batteries as Power Supply.

This contribution describes direct current insulator-based electrokinetic (DC-iEK) microfluidic devices stimulated by 9 V alkaline batteries for the trapping of 2-µm diameter fluorescent polystyrene particles. These devices featured two triangular insulating posts within the fluidic channel. Particle trapping was clearly observed at 18 V (two 9 V batteries connected in series), but only intermittent particle trapping was observed with a single 9 V battery. Particle trapping was determined by measuring the increase in relative fluorescence intensity at the gap region between the single pair of triangular posts. Results demonstrate that the use of low stimulating voltages (deemed as ultralow) in DC-iEK systems may be more suitable for accurate and precise electrokinetic characterization of particles-by exhibiting a very well-localized trapping region with negligible particle oscillations therein, respectively-than for high-performance and high-throughput particle manipulation (i.e., concentration, separation, filtering, or isolation).