Cellular Deformations Induced by Conical Silicon Nanowire Arrays Facilitate Gene Delivery

Abstract

Engineered cell–nanostructured interfaces generated by vertically aligned silicon nanowire (SiNW) arrays have become a promising platform for orchestrating cell behavior, function, and fate. However, the underlying mechanism in SiNW‐mediated intracellular access and delivery is still poorly understood. This study demonstrates the development of a gene delivery platform based on conical SiNW arrays for mechanical cell transfection, assisted by centrifugal force, for both adherent and nonadherent cells in vitro. Cells form focal adhesions on SiNWs within 6 h, and maintain high viability and motility. Such a functional and dynamic cell–SiNW interface features conformational changes in the plasma membrane and in some cases the nucleus, promoting both direct penetration and endocytosis; this synergistically facilitates SiNW‐mediated delivery of nucleic acids into immortalized cell lines, and into difficult‐to‐transfect primary immune T cells without pre‐activation. Moreover, transfected cells retrieved from SiNWs retain the capacity to proliferate—crucial to future biomedical applications. The results indicate that SiNW‐mediated intracellular delivery holds great promise for developing increasingly sophisticated investigative and therapeutic tools.

Silicon‐Nanotube‐Mediated Intracellular Delivery Enables Ex Vivo Gene Editing

“…Similar viability (>90%) was observed for the cells detached from flat Si and SiNTs after 6 h incubation (Figure S7e, Supporting Information). Furthermore, to track the proliferation of the harvested cells, we stained GPE86 cells with CellTrace Violet (CTV) dye [ 8 ] before seeding onto flat Si and SiNT substrates. After 6 h incubation, cells were detached from both substrates and divided into four groups.…”

“…Highly efficient silicon nanowire (SiNW)‐mediated intracellular delivery has employed arrays of either solid [ 8–10 ] or porous [ 11–13 ] SiNWs, preloaded with diverse biomolecule cargoes of interest. The Melosh group demonstrated for the first time the development of a delivery platform based on nanostraws (hollow nanowires) integrated into a microfluidic device.…”

Nanoneedle Platforms: The Many Ways to Pierce the Cell Membrane

“…Due to the minimal physical perturbation of nanoneedles to the cells, various primary cells including primary immune cells, neuron cells, and stem cells are modulated by nanoneedles for drug delivery or cell manipulation. [ 69,116,117 ] In addition to in vitro cellular investigations, recent progresses exploring the nanoneedles for in vivo biomedical applications have been reported, significantly promoting the clinical translational and therapeutic utility.…”

“…Recently, Chen et al successfully transfected adherent and nonadherent cell lines using mechanical penetration by Si nanowire arrays, where the delivery results were examined by flow cytometry. [ 69 ] 30% transfection efficiency for primary mouse T cells was achieved, without eliciting immune activation.…”

“…Perhaps more importantly, these physical systems appear to work with many primary cell types, such as immune cells and stem cells that are difficult to work with using traditional techniques. [ 67–69 ] As the utility of nanoneedle arrays grows, it is of critical importance to understand the influence of the nanoneedles on the target cells. [ 70–72 ] Nanoneedles can eventually serve as an alternative signaling cue for precisely controlling complex cellular functions such as adhesion, [ 73,74 ] proliferation, [ 75,76 ] migration, [ 77,78 ] and differentiation, [ 79,80 ] and nonspecific or deleterious perturbations [ 81 ] must be understood and mitigated.…”