Nanoneedle-Mediated Stimulation of Cell Mechanotransduction Machinery

Abstract

Biomaterial substrates can be engineered to present topographical signals to cells which, through interactions between the material and active components of the cell membrane, regulate key cellular processes and guide cell fate decisions. However, targeting mechanoresponsive elements that reside within the intracellular domain is a concept that has only recently emerged. Here, we show that mesoporous silicon nanoneedle arrays interact simultaneously with the cell membrane, cytoskeleton, and nucleus of primary human cells, generating distinct responses at each of these cellular compartments. Specifically, nanoneedles inhibit focal adhesion maturation at the membrane, reduce tension in the cytoskeleton, and lead to remodeling of the nuclear envelope at sites of impingement. The combined changes in actin cytoskeleton assembly, expression and segregation of the nuclear lamina, and localization of Yes-associated protein (YAP) correlate differently from what is canonically observed upon stimulation at the cell membrane, revealing that biophysical cues directed to the intracellular space can generate heretofore unobserved mechanosensory responses. These findings highlight the ability of nanoneedles to study and direct the phenotype of large cell populations simultaneously, through biophysical interactions with multiple mechanoresponsive components.

Cellular Deformations Induced by Conical Silicon Nanowire Arrays Facilitate Gene Delivery

“…The number of parameters in play at the cell–SiNW interface, and their complex and dynamic interactions, present a key challenge in delineating how decisions of cell behavior such as cell morphology, cytoskeleton arrangement, focal adhesion formation, motility, and other cellular processes are orchestrated. For example, focal adhesions have long been speculated to play a central role in cellular migration and regulation of both mechanical and biochemical signaling pathways . To better understand the cell proteins and complexes that participate in focal adhesion on SiNWs, we examined the distribution of F‐actin, β‐integrin (transmembrane receptor), and vinculin (membrane‐cytoskeletal protein), which are reported to play important roles in mediating cell adhesion to the extracellular matrix .…”

High‐Aspect‐Ratio Nanostructured Surfaces as Biological Metamaterials

“…Interestingly, the authors suggest that coatings of just fibronectin or laminin (some of the main protein components of extracellular matrix) resulted in the formation of focal adhesions that locally perturbed the membrane resulting in a larger gap than the polylysine‐based coatings . Given the ability of high‐aspect‐ratio nanostructures to impact the formation of focal adhesions (discussed later in this review), this further hints at the complexity of the interplay between topography and chemistry, suggesting that care is required when selecting surface coatings.…”

“…With appropriate staining, confocal microscopy allows the interface to be imaged in three dimensions. Super‐resolution microscopy techniques are less common, but are becoming increasingly useful to visualize the localization of subcellular components . Chien et al used stochastic optical reconstruction microscopy (STORM, which uses the intermittent blinking of fluorophores to exceed normal resolution limits) to show how cells can form mature focal adhesions by deforming polymer nanopillars .…”

“…Chien et al used stochastic optical reconstruction microscopy (STORM, which uses the intermittent blinking of fluorophores to exceed normal resolution limits) to show how cells can form mature focal adhesions by deforming polymer nanopillars . Structured‐illumination microscopy has also been used to visualize the formation of lamin A (a structural protein) rings in the nuclear membrane, around silicon nanoneedles …”

“…In some reports, multiple geometries were fabricated, here a representative geometry is shown.) Inset: Microscopy image of FIB‐SEM milled cross‐section of a human mesenchymal stem cell interfacing porous silicon nanoneedles, scale bar 2 µm: Adapted under the terms of the ACS AuthorChoice with CC BY license ( https://creativecommons.org/licenses/by/4.0/) . Copyright 2019, The Authors, published by ACS.…”