Size-Tunable Nanoneedle Arrays for Influencing Stem Cell Morphology, Gene Expression, and Nuclear Membrane Curvature

Abstract

High-aspect-ratio nanostructures have emerged as versatile platforms for intracellular sensing and biomolecule delivery. Here, we present a microfabrication approach in which a combination of reactive ion etching protocols were used to produce high-aspect-ratio, nondegradable silicon nanoneedle arrays with tip diameters that could be finely tuned between 20 and 700 nm. We used these arrays to guide the long-term culture of human mesenchymal stem cells (hMSCs). Notably, we used changes in the nanoneedle tip diameter to control the morphology, nuclear size, and F-actin alignment of interfaced hMSCs and to regulate the expression of nuclear lamina genes, Yes-associated protein (YAP) target genes, and focal adhesion genes. These topography-driven changes were attributed to signaling by Rho-family GTPase pathways, differences in the effective stiffness of the nanoneedle arrays, and the degree of nuclear membrane impingement, with the latter clearly visualized using focused ion beam scanning electron microscopy (FIB-SEM). Our approach to design high-aspect-ratio nanostructures will be broadly applicable to design biomaterials and biomedical devices used for long-term cell stimulation and monitoring.

Assessing the impact of silicon nanowires on bacterial transformation and viability of Escherichia coli

“…In the eukaryotic literature, subtle differences in nanostructure geometry can strongly impact cellular response. 41 In this work, we have attempted to replicate the dimensions of naturally occurring surfaces, however exploring parameters such as nanowire spacing may offer access to a greater range of bacterial cell responses.…”

Tailoring Cellular Function: The Contribution of the Nucleus in Mechanotransduction

“…Recently, Seong et al showed how stem cell gene expression could be modulated by means of nanoneedle arrays. Here, lamin genes, YAP transcription, and focal adhesion gene expression were varied by changing nanoneedle distribution and structural features ( Seong et al, 2020 ).…”

High Throughput and Highly Controllable Methods for In Vitro Intracellular Delivery

“…Nanostructure substrates ( Figure 2E) are a group of methods utilizing 1D structures such as nanoneedles, [107,110] nanowires, [111][112][113][114][115][116][117] nanotubes, [118,119] and nanostraws [120][121][122][123] with diameters small enough that when cells are adhered to them they either induce spontaneous penetration, alter membrane permeabilization, or elicit endocytosis for molecular delivery. There is an ongoing debate as to which of these mechanisms or combination of mechanisms is primarily responsible for delivery using nanostructures.…”