Proposal and experimental validation of the electrophoretic Coulter method for analyzing microparticles and biological cells

Zeta potential measurement is one of the simplest methods for analyzing the electrical surface properties of microparticles and biological cells in a solution. The authors propose a new methodology for simultaneous measurement of the number, size and zeta potential of different specimens in a microchannel, referred to as the electrophoretic Coulter (EC) method. First, a microchannel is fabricated using soft lithography, a small amount of a specimen is injected into it, and ion current modulation through the microchannel is measured while a DC electric field is applied. The results are then compared with those obtained using the conventional methods involving dynamic light scattering (DLS) method and microscopy. The results of the EC method show good agreement with those of the conventional approaches. Accordingly, the technique enables high-throughput analysis of different specimens including nano materials and biomolecules using a micro/nanochannel, thereby significantly contributing to the field of bio-nano fusion research.