The effect of silica nanoparticle-modified surfaces on cell morphology, cytoskeletal organization and function

Abstract

Chemical and morphological characteristics of a biomaterial surface are thought to play an important role in determining cellular differentiation and apoptosis. In this report, we investigate the effect of nanoparticle (NP) assemblies arranged on a flat substrate on cytoskeletal organization, proliferation and metabolic activity on two cell types, Bovine aortic endothelial cells (BAECs) and mouse calvarial preosteoblasts (MC3T3-E1). To vary roughness without altering chemistry, glass substrates were coated with monodispersed silica nanoparticles of 50, 100 and 300 nm in diameter. The impact of surface roughness at the nanoscale on cell morphology was studied by quantifying cell spreading, shape, cytoskeletal F-actin alignment, and recruitment of focal adhesion complexes (FAC) using image analysis. Metabolic activity was followed using a thiazolyl blue tetrazolium bromide assay. In the two cell types tested, surface roughness introduced by nanoparticles had cell type specific effects on cell morphology and metabolism. While BAEC on NP-modified substrates exhibited smaller cell areas and fewer focal adhesion complexes compared to BAEC grown on glass, MC3T3-E1 cells in contrast exhibited larger cell areas on NP-modified surfaces and an increased number of FACs, in comparison to unmodified glass. However, both cell types on 50 nm NP had the highest proliferation rates (comparable to glass control) whereas cells grown on 300 nm NP exhibited inhibited proliferation. Interestingly, for both cell types surface roughness promoted the formation of long, thick F-actin fibers, which aligned with the long axis of each cell. These findings are consistent with our earlier result that osteogenic differentiation of human mesenchymal progenitor cells is enhanced on NP-modified surfaces. Our finding that nanoroughness, as imparted by nanoparticle assemblies, effects cellular processes in a cell specific manner, can have far reaching consequences on the development of “smart” biomaterials especially for directing stem cell differentiation.

Stochastic nanoroughness modulates neuron–astrocyte interactions and function via mechanosensing cation channels

“…Because macromolecules are in a state of high entropy, and entropy is a statistical measure of randomness, the roughness presented by macromolecules is expected to be stochastic (random). We simulated random ECM nanoroughness using an assembly of monodispersed silica colloids of increasing size (10,24) (Fig. 1A).…”

“…However, developmental processes such as axon pathfinding, synapse formation, nervous system patterning, neuronal plasticity, and degeneration fail to be explained solely on the basis of soluble factors. There is increasing evidence that physical variables such as the stiffness of a cellular environment influence cell development (7)(8)(9)(10)(11)(12). However, the cells of the brain tissue reside in a soft environment that is rich in polysaccharides (13,14).…”

Integrating Mechanical and Biological Control of Cell Proliferation Through Bioinspired Multieffector Materials

“…Alternatively, several categories of particulate materials have been explored for the nanomorphological modification of scaffold surfaces (bottom-up approach), including ceramics, polymers and nanotubes (19,20,21,22) . Particle-based surface decoration is highly promising since it is less dependent on the chemical nature of the scaffold material in contrast to lithographical modification.…”

Nanodentistry: Combining Nanostructured Materials and Stem Cells for Dental Tissue Regeneration

“…ECM provides nanoscale structures, such as the 15-300 nm in diameter collagen fibrils that allow cell adhesion (via integrins) and immobilization of signaling molecules, thus influencing the fate and behavior (i.e., proliferation, migration and differentiation) of stem cells [107]. The concentration, size, spacing, surface chemistry and shape (e.g., ridges, grooves, pores and pits) of the artificial nanostructures (e.g., nanotubes and nanolines) are important parameters for the development of cell adhesion sites that monitor stem cell behavior [108][109][110]. For example, it has been shown that surface irregularity (e.g., nanoline grating) and diverse surface chemistries (e.g., silica and poly[methyl methacrylate]) are capable of enhancing adhesion, alignment, growth and differentiation of stem cells [108,109].…”