Electric field enhanced 3D scalable low-voltage nano-spike electroporation system

Electroporation (EP) is one of the most widely used methods for the introduction of bio-molecules into the cells due to its high efficiencies, simplicity, and safety. Previous macro- and micro-scale EP systems suffer from drawbacks such as costly and time-consuming fabrication processes, high voltage operation causes undesirable electrochemical reactions, low cell viabilities, and electrode degradation. In this paper, we presented a low-cost three-dimensional (3D) scalable nano-spike electroporation system for efficient molecules delivery with high cell viabilities at low applied voltages. Arrays of 3D Aluminum (Al) nano-spikes (NSPs) were fabricated through scalable, reproducible and cost effective electrochemical anodization and etching processes. Due to scalability of the fabrication process, 3D NSPs were fabricated on chips as well as at the wafer level for large scale processing. 3D nano-spike electroporation (NSP-EP) chips were capable of handling small cell populations (100-500) while NSP-EP wafers can handle large cell populations (104-105). Electroporation at low voltages is obtained due to electric field enhancement at high-aspect-ratio NSPs. With same electric field strength, high EP efficiencies ƞEP and cell viability фcell (>93 ± 6%) were obtained at more than ten times lower voltages (2 V) on NSP-EP chips as compared to planar electroporation (PEP) devices without NSPs. By optimizing electric pulse parameters and nano-spikes dimensions, NSP-EP chip performance was enhanced by minimizing undesirable electrochemical reactions and electrolysis that were observed on PEP devices due to high voltage operations.