Maximizing Transfection Efficiency of Vertically Aligned Silicon Nanowire Arrays

Abstract

Vertically aligned silicon nanowire (VA‐SiNW) arrays are emerging as a powerful new tool for gene delivery by means of mechanical transfection. In order to utilize this tool efficiently, uncertainties around the required design parameters need to be removed. Here, a combination of nanosphere lithography and templated metal‐assisted wet chemical etching is used to fabricate VA‐SiNW arrays with a range of diameters, heights, and densities. This fabrication strategy allows identification of critical parameters of surface topography and consequently the design of SiNW arrays that deliver plasmid with high transfection efficiency into a diverse range of human cells whilst maintaining high cell viability. These results illuminate the cell‐materials interactions that mediate VA‐SiNW transfection and have the potential to transform gene therapy and underpin future treatment modalities.

Cellular Deformations Induced by Conical Silicon Nanowire Arrays Facilitate Gene Delivery

“…Despite the efficient delivery of various biological molecules into cells using NWs,17a,22,44 it is essential to prove that cells detached from SiNWs maintain high viability and proliferative capacity—prerequisites for potential application in cell‐based immunotherapy. We followed the viability of cells cultured on SiNWs and tracked their proliferation up to 3 days after detaching from SiNWs.…”

High‐Aspect‐Ratio Nanostructured Surfaces as Biological Metamaterials

“…Stochastic processes can be rapid and affordable but lack precise control and can result in a wide distribution of feature sizes. This is potentially problematic where consistent surfaces are required for cell interactions, which some researchers have argued is essential for maximizing the reproducibility of results …”

“…Nanosphere lithography (also referred to as colloidal lithography) uses the self‐assembly of polymer or microgel‐based nanospheres on a surface . A wide range of variants exist, for a more in depth discussion see the review of Wang et al Controlling the type and size of particle deposited, the surface chemistry, and deposition conditions allows either well‐defined high‐density packing or lower‐density stochastic patterns …”

“…Limitations include the challenge of achieving uniform, regular self‐assembly of the spheres without packing defects between different regions and a lack of design flexibility. The interaction between spheres means parameters such as pitch spacing and nanopillar diameter is interdependent …”

“…E) Porous silicon nanoneedles for in vivo growth factor delivery into muscle tissue . F) Silicon nanowire arrays for cell transfection . G) Vertical nanowire electrode arrays for interfacing neuronal cells .…”