Design and testing of the oblique and V-shaped Cu-ITO microelectrode arrays to generate dielectrophoretic force on red blood cells

Dielectrophoresis (DEP) is a phenomenon in which a force is applied to a particle induced by a gradient of an electric field. The dielectrophoretic technique is popular for manipulating bioparticles, because it requires only a small sample, is label-free, rapid, and inexpensive. Manipulation of biosample can be in the form of monitoring, separation, sorting, capturing, etc., so that the DEP method can be applied as a biosample analysis tool. However, research on the application of the DEP method is still developing on various electrode arrays and bioparticles. In this work, a lab-on-chip device with an oblique and V-shaped 3D microelectrode array has been developed to manipulate red blood cells (RBCs) using the dielectrophoresis (DEP) method. The microelectrodes were fabricated with copper and indium tin oxide films on a glass substrate, while the microchannel was constructed using double-sided tape insulators. RBCs samples were prepared in deionized water and EDTA medium with an electrical conductivity of 1.5 S/m. The test of dielectrophoretic force characteristics on RBCs was carried out by applying an AC signal to the microelectrode, and the phenomenon was observed using a microscope with a CCD camera. The results showed that negative DEP forces were observed at frequencies of 5-7 MHz, 3.5–5 MHz, and 2-4 MHz in the oblique electrode spacing area and in the middle area of the V-shaped electrode curve. While positive DEP forces were observed at frequencies of 8–14 MHz, 6–13 MHz, and 5–11 MHz in the edge area of the oblique electrode and in the inner tip area of the V-shaped electrode curve, respectively at voltages of 5 Vpp, 10 Vpp, and 15 Vpp. The results of this work show the promising potential of lab-on-chip devices with oblique and V-shaped microelectrode arrangements to manipulate particularly RBCs and generally bioparticles so that biosamples can be further analyzed.