Minimally invasive intracellular delivery based on electrokinetic forces combined with vibration-assisted cell membrane perforation

To provide an effective platform for the fundamental analysis of cellular mechanisms and the regulation of cellular functions, we developed a unique method of minimally invasive intracellular delivery. Using this method, we successfully demonstrated the delivery of DNA molecules into living HeLa cells via a glass micropipette based on DC-biased AC-driven electrokinetic forces with much better controllability than that of the pressure-driven flow method. We also proposed a vibration-assisted insertion method for penetrating the cell membrane to reduce cell damage. Preliminary insertion tests revealed that application of mechanical oscillation can reduce the deformation of cells due to increases in their viscous resistance, resulting in a high probability of cell membrane perforation and cell viability. Moreover, to overcome the intrinsic low throughput of intracellular delivery with a single glass micropipette, we developed a fabrication process involving an array of stepped hollow silicon dioxide (SiO2) nanoneedles with well-defined tips.