The effects of surface topography of nanostructure arrays on cell adhesion

Abstract

Nanostructure arrays have drawn much attention and are promising as new biomaterials in the field of biomedicine. In recent years, numerous experimental studies on the cell behavior of nanostructured arrays (NSs) have been published, describing a wide variety of experimental results. But there are only a few theoretical analyses that elucidate the mechanisms of interactions between cells and nanostructures. Here we present a quantitative thermodynamic model to elucidate the effects of surface topography of nanostructure arrays on cell adhesion. Based on the established model, we studied the equilibrium state of cell adhesion by analyzing the change in free energy during the adhesion process. Theoretical results showed that cell adhesion mode is actually determined by the balance between adhesion energy and deformation energy of the cell membrane. According to the calculated results, a phase diagram of the cell adhesion has been constructed, which can clarify the interrelated effects of the radius and surface distribution density of nanopillars. We can identify the relation between the surface topography of nanostructure arrays and the cell adhesion mode from the phase.

High‐Aspect‐Ratio Nanostructured Surfaces as Biological Metamaterials

“…Models broadly consist of continuum type, where the membrane is treated like a continuous sheet that can be characterized by key parameters such as tension or stiffness; or molecular‐based simulations, which attempt to simulate the interactions between constituent molecules directly. Elastic theory models, as first proposed by Helfrich, consider the balance of forces or free‐energy at the cell–substrate interface . These have the benefit of rapidly showing an ensemble response, at the expense of the role of complex molecular interactions on membrane disruption .…”

“…More recently, Zhou et al attempted to expand on this approach, to accommodate the impact of nanostructure diameter, by expressing the change in bending energy as three separate terms: membrane unfolding, stretching, and edge effects . Their model predicts that for realistic nanostructure densities (25–100 nanostructures per 100 µm 2 ), sharper nanostructures tend to favor greater membrane deformation over blunt ( Figure ).…”

“…The black and white lines indicate the boundary for cells either being a fully‐engulfed “bottom” or “top” state. Reproduced with permission . Copyright 2018, Royal Society of Chemistry.…”

Antibacterial Nanopillar Array for an Implantable Intraocular Lens

“…The diameter and nanopillar densities were designed to prevent the adhesion of the corneal cells. [ 34,35 ] The NPA was subsequently coated with a 50 nm thick, crosslinked ionic polymer thin film (pVD).…”

“…The adhesion of the HCE cells to the NPA structure can be sufficiently suppressed through a systematic adjustment of the dimension and density of the NPA. [ 34 ] The reduction in HCE adhesion on NPA would be highly advantageous when integrated into the IOL, because the IOL modified with pVD‐coated NPA can sufficiently suppress the formation of the multicellular structure, thereby preventing the outbreak of PCO after the IOL injection. [ 11 ] The biocompatibility was verified using HCE cells that were cultured using a pVD‐coated NPA‐immersed medium.…”