Experimental study on filtering, transporting, concentrating and focusing of microparticles based on optically induced dielectrophoresis

Abstract

The key problem to be solved for the dielectrophoresis (DEP) application is to provide dynamically reconfigurable microelectrodes and low-cost methodology for bioparticle manipulation. The emergence of optically induced DEP (ODEP) based on photoconductive effect provides a potential solution for the above problem. In this paper, an ODEP chip is designed and fabricated, and the corresponding experimental platform was established, whereupon four types of particle manipulation regimes-filtering, transporting, concentrating and focusing based on ODEP are experimentally demonstrated and the operating performances are quantitatively analyzed. The experiment results show that the functions and performances of ODEP manipulation are heavily dependent on the geometrical shape, scales and speed of optical patterns, actuating signal frequency and the electric conductivity of the solution. The manipulation efficiency can increase by more than 50% via increasing the optical line width. Moreover, the efficiency is obviously affected by the inclination angle of the optical oblique lines in the manipulation of particle focusing. Additionally, the maximum velocity of particles increases with the increment of the inside radius and the thickness of the optical trapping ring. Particle manipulation efficiency is always related to signal frequency and solution conductivity, and empirically, satisfactory performance and high efficiency are obtained when the solution electric conductivity ranges from 5×10−4 S/m to 5×10−3 S/m.