A Highly Dense Nanoneedle Array for Intracellular Gene Delivery

We present a dense needle array with sharp nano-tips for intracellular gene and drug delivery, with the ultimate goal of gene correction in a high throughput manner. The nanoneedles are fabricated using isotropic dry etching of silicon, followed by anisotropic dry etching and thermal-oxidation-based tip sharpening. The nanoneedle density is as large as 10 needles per square centimeter. In-vitro intracellular delivery tests demonstrated that the nanoneedle array can effectively deliver molecular probes into cells without causing significant cell death from cell membrane penetration. Uptake of molecular probes by up to 34% of cells after nanoneedle treatment was observed.