Droplet-based dielectrophoresis device for on-chip nanomedicine fabrication and improved gene delivery efficiency

In this article, we present the design, fabrication, and experimental verification of a droplet-based microfluidic device for effective on-chip fabrication and separation of polymer-based nanoparticles using dielectrophoresis (DEP) effect. The separated polyplexes nanoparticles were used in cells for improved gene transfection efficiency. By adjusting the flow rate of PEI₆₀₀-CyD-FA (H₁) and DNA plasmids, polyplexes products can be mixed and self-assembled inside droplets within approximately a nanoliter volume. This procedure ensures synthesized particles to have a narrow size distribution. In addition, a new microchannel design was developed to automatically coalesce two moving aqueous droplets and to directly extract aqueous polyplex products from oil. Finally, the H₁-DNA polyplexes of ~116 nm diameter were separated via negative DEP force under 8 V_peak–peak and 20 MHz conditions by passing three times through a non-uniform electric field. The biological findings demonstrated that the DEP-treated polyplexes still possessed the ability to enter HUVEC cells and that the gene transfection efficiency was raised to 15 %, as opposed to the control group’s 4 % where the polyplexes had no DEP treatment. The quantitative comparison was done by counting the number of cells produced via positive EPFG expression. These hydrodynamic and electrodynamic techniques provide an integrated microfluidic platform for fabricating and screening nanoscale drugs.