An anti-adhesion technique in microfluidic channel using dielectrophoresis for particle processing microfluidic chip applications

Particle adhesion to the walls of microfluidic channels is a prominent cause of deteriorating performance and reliability in miniaturized analytical devices; it can also cause unexpected changes in their structures and operating conditions. Therefore, the demand of anti-adhesion for wall loss reduction on particle processing chips is high. This paper demonstrates an anti-adhesion technique using dielectrophoresis. The proposed technique is applied to a distribution microchannel for a feasibility test and is then applied to a blood plasma filter, which is a human blood cell and plasma separation device. In the distribution microchannel, the application of electric potentials of 0-20 V_PP at 3 MHz caused the wall loss of polystyrene latex (PSL) particles to decrease with decreasing particle diameter. When an electric potential of 20 V_PP was applied in a distribution microchannel experiment using PSL particles, the wall loss decreased by 52.7±3% for 10-μm-diameter particles. On the other hand, when a 20 V_PP electric potential was applied in a distribution microchannel experiment using human blood cells, the wall loss decreased by 66.4±6%. In the blood plasma filter, the wall loss decreased by 54.89±5% at 20 V_PP and 1 MHz. The purity efficiency of the blood plasma filter was 69.56% without the wall loss reduction technique and 95.14% when the applied electric potential was 20 V_PP.