Emerging Roles of 1D Vertical Nanostructures in Orchestrating Immune Cell Functions

Abstract

nanotopographies optimized to facilitate biomolecular delivery, genome editing, and cellular modulation-have enormous potential to build capacity over a range of collaborating disciplines associated with biomedical research. High-aspect-ratio nanostructures are now providing major advantages in precise manipulation of increasingly complex cellular processes, assisting the translation into clinical applications such as tissue engineering, regenerative medicine, drug delivery, biosensing, and cancer immunotherapies. [2-5] In particular, 1D vertical nanostructures (1D-VNS)-nanowires, nanoneedles, nanopillars, nanotubes, nanosyringes, nanostraws, nanocones, and nanospikes (Figure 1a)-have helped tackle various biological problems such as intracellular recording and genetic interrogation. [6-16] Unlike other highaspect-ratio nanostructures, such as freestanding carbon nanotubes, 1D-VNS can be rationally designed and synthesized, via top-down and/or bottom-up approaches, with defined key parameters-including topological geometry (pitch, diameter, length), chemical composition, doping, and electronic propert ies. [17-21] So by well-controlled programming coupled with selective surface functionality, 1D-VNS can provide unprecedented spatial and mechanical resolution to enable direct, Engineered nano-bio cellular interfaces driven by 1D vertical nanostructures (1D-VNS) are set to prompt radical progress in modulating cellular processes at the nanoscale. Here, tuneable cell-VNS interfacial interactions are probed and assessed, highlighting the use of 1D-VNS in immunomodulation, and intracellular delivery into immune cells-both crucial in fundamental and translational biomedical research. With programmable topography and adaptable surface functionalization, 1D-VNS provide unique biophysical and biochemical cues to orchestrate innate and adaptive immunity, both ex vivo and in vivo. The intimate nanoscale cell-VNS interface leads to membrane penetration and cellular deformation, facilitating efficient intracellular delivery of diverse bioactive cargoes into hard-to-transfect immune cells. The unsettled interfacial mechanisms reported to be involved in VNS-mediated intracellular delivery are discussed. By identifying up-to-date progress and fundamental challenges of current 1D-VNS technology in immune-cell manipulation, it is hoped that this report gives timely insights for further advances in developing 1D-VNS as a safe, universal, and highly scalable platform for cell engineering and enrichment in advanced cancer immunotherapy such as chimeric antigen receptor-T therapy.

High Throughput and Highly Controllable Methods for In Vitro Intracellular Delivery

“…There is an ongoing debate as to which of these mechanisms or combination of mechanisms is primarily responsible for delivery using nanostructures. [ 124 ] Following penetration, the cell membrane seals around the base of the structure. Intracellular delivery can occur through molecules adsorbed to the surface, as is the case with solid nanoneedles, solid nanopillars, solid nanowires, and nanotubes sealed at one end; or by permanent intracellular access provided by hollow nanostructures such as hollow nanoneedles, nanotubes, and nanowires.…”

High Aspect Ratio Polymeric Nanoneedle Arrays

“…High aspect ratio (HAR) nanostructures are of particular interest as they undergo unique and close interactions with biological membranes. [ 23,41–47 ] Tailoring of the geometry of HAR nanostructures is key to their application as this influences the cell–surface interaction. [ 42,43,48,49 ] Silicon, carbon, and diamond are commonly used materials for nanostructure fabrication as high modulus materials are well‐suited to support ultra‐high resolution features.…”

Optically Transparent Vertical Silicon Nanowire Arrays for Live-Cell Imaging

“…Thus, the development of new tools for directly probing this response is likely to lead to the development of novel fundamental research applications and ex vivo cell-based therapies. [16][17][18][19] The ability of these nanostructures to elicit functional cellular responses at the cell-material interfacesuch as intracellular delivery, biomolecular extraction (nanobiopsy), nanoelectrode-based electrophysiology, biosensing, and mechanotransduction-arises from their salient advantages in multiple independent parameters: geometric/architectural exibility, minimal invasiveness, and the ability to simultaneously interface with large numbers of cells. [20][21][22][23][24][25] Despite implementation of these platforms in a variety of advanced cellular applications-such as in vivo and ex vivo gene editing, recording cellular action potential, and immunomodulation-the development of this burgeoning eld is hindered by a lack of tools allowing for direct, rapid, and dynamic visualization of living cells interacting with these nanostructures.…”