Nano-Orifice Based Dielectrophoretic Manipulation and Characterization of Micro-target

This study introduces an innovative continuous microfluidic DC-dielectrophoresis (DC-DEP) technique for micro/nanoparticle separation using pressure-driven flow. The method employs asymmetric orifices (large-small configuration) on the channel walls to establish a non-uniform electric field through low-voltage application. As particles traverse the high-field-gradient region near the small orifice, differential DEP responses (positive/negative) are induced based on their size and dielectric properties. By optimizing applied potentials and electrolyte conductivity, the system enables effective size-based separation of polystyrene nanoparticles down to nanoscale dimensions. Compared to conventional DC-DEP devices that rely on physical obstacles for field non-uniformity, this design achieves superior performance through localized electric field enhancement without requiring complex microstructures. Key advantages include reduced Joule heating due to localized low-voltage operation (typically <10 V) and extended applicability for nanoparticle processing.