Dynamic Assembly of Polyplex in Hybrid Flow for Gene Delivery

Polyplex, such as DNA-polyethylenimine (PEI) complex, has recently been explored for nonviral gene delivery. However, undesirable transfection efficiency is often observed. As the structure of polyplex greatly affects the cellular entry, the intracellular trafficking, and DNA release, we hypothesis that efficient regulation of its dynamic assembly process will achieve appropriate structure of the polyplex as well as better delivery efficiency. We developed a new microdevice to produce DNA-PEI nanoparticles in a hybrid flow field. With a continuous flow operation, DNA plasmids or PEI molecules are concentrated around the other for better dynamic assembly efficiency. The effects of DNA conformations (e.g., coil/stretching), particle size, and structures are examined at different N:P ratios. The in vitro transfection efficiency of these polyplex to mammalian cells is also examined.