3D Si-based nanochannel platform for robust cell electroporation

Electroporation is a cellular delivery method making use of a voltage pulse to propel exogenous material through the cell membrane and into the cell allowing the modification of a given cell or cell population. An ideal electroporation system would possess four characteristics encompassing the benefits of all these systems: (1) high throughput, (2) high cell viability, (3) excellent deliver efficiency, and (4) controlled dosage. Many advances^1-2 in cell electroporation allow for high throughput, high cell viability, or excellent dosage control, yet no platform is available for the combination of all three. In this work, we show a "3D nanochannel electroporation (NEP) system" (Fig. 1a) on a silicon-chip platform designed to meet these three criteria. This "NEP chip" is patterned on one side using a ∼500 nm circle array and the other using a 50 μm array. Each pattern is then etched through until connection is established as shown in Fig. 1b. The etching of the 3D NEP chip is done using the Bosch process, a combination of SF₆ and C₄F₈ plasma chemistries giving a highly directional etch for creation of high aspect ratio features. The result is a 3D nanochannel array consisting of nanopores that are ∼500 nm in diameter and 20-25 μm deep. The backside microchannel array consists of wells that are 50 μm in diameter and ∼225-230 μm deep.