Continuous Vector-free Gene Transfer with a Novel Microfluidic Chip and Nanoneedle Array.

Delivery of foreign cargoes into cells is of great value for bioengineering research and therapeutic applications. In this study, we proposed and established a carrier-free gene delivery platform utilizing staggered herringbone channel and silicon nanoneedle array, to achieve high-throughput in vitro gene transfection. With this microchip, fluidic microvortices could be induced by the staggered-herringbone-shaped grooves within the channel, which increased the contact frequency of the cells with the channel substrate. Transient disruptions on the cell membrane were well established by the nanoneedle array on the substrate. Compared to conventional nanoneedle-based delivery system, proposed microfluidic chip achieved flow-through treatment with high gene transfection efficiency (higher than 20%) and ideal cell viability (higher than 95%). It provides a continuous processing environment that can satisfy the transfection requirement of a large amounts of biological molecules, showing high potential and promising prospect for both basic research and clinical application.