Tapered Dielectrophoresis Microelectrodes: Device, Operation, and Application

Dielectrophoresis, the induced lateral or vertical motion of a polarizable particle in a nonuniform electric field has been demonstrated to perform selective detection and rapid manipulation in the microfluidics system. The capability to combine both lateral at y-axis and vertical at z-axis motion is always required as it allows enhancements of sensitivity, selective detection, and rapid manipulation, mostly in medical applications. We have introduced a technique to determine lateral and vertical motions using dielectrophoresis forces (FDEP) simultaneously. Utilization of a new configuration of a tapered sidewall profile, dielectrophoresis (DEP) microelectrodes arrays with higher intensity electric field gradient at bottom and top edge of microelectrodes could be created. This configuration enabled two different directions of motion by obtaining a new crossover frequency called adjustment frequency (fadj) within the value between the crossover frequency (fxo) of targeted and untargeted particles. The target particles could be biological cells in a mixture of cells with various physical and chemicals properties. The special design of tapered microelectrodes arrays enabled FDEPfor selective detection and rapid manipulation of targeted species at two different locations, which are at the top surface and in between of two tapered DEP microelectrodes. The implementation of tapered DEP microelectrodes could provide a novel DEP platform for contactless electrically driven detection and manipulation at higher efficiency.