The Effect of Si Nano-Columns in 2-D and 3-D on Cellular Behaviour: Nanotopography-Induced CaP Deposition from Differentiating Mesenchymal Stem Cells

Abstract

Si nano-columns were deposited in 2-D and 3-D in the form of well-defined geometries by physical vapor deposition. The films were grown by e-beam evaporation with an angle between source and substrate. The Si nano-columns were deposited in the shape of spiral with two different incoming atomic flux angle so that the manipulation of nano-columns in 3-D (out-of-plane) was obtained. The Si nano-columns were also grown as vertical stick with square, triangle and linear cross sections in 2D (in-plane). Rat bone marrow mesenchymal stem cells (MSCs) were cultured on these different Si nanosurfaces. MTS assay was carried out to determine the cell proliferation and viability based on different nanotopographies. For the evaluation of cell distribution and morphology, a SEM (Scanning Electron Microscopy) analysis was performed. Any CaP deposition on Si nanosurfaces was observed using energy dispersive X-Ray spectroscopy in SEM (SEM-EDX). After 4 days of culture, there was a higher value of cell proliferation on square columns and spiral Si nano-columns grown with 85 degrees of incoming atomic flux. The cell attachment and spreading was also affected by the geometry of Si nano-columns. While there were still cells showing round/spherical morphology with minimal spreading on conventional Si surfaces, most of the cells cultured on different Si nanotopographies attached on the surface and displayed flattened morphology, especially on the square columns surface. Moreover, CaP deposition was discovered on square columns and spiral films with 85 degrees substrate angle. So, it can be concluded that there is a clear correlation between cell responses and nano-sized geometry on Si surface and it is possible to induce cellular differentiation and CaP formation in certain geometrical constraints.

Bactericidal effects of nanopatterns: A systematic review

“…Therefore, those nanopatterns, which are lethal to the bacteria, could possibly trigger direct or indirect mechanotransduction pathways within mammalian cells affecting their function. For instance, it has been shown that the osteogenic differentiation of MSCs is sensitive to a variety of factors including the spatial arrangement of the nanopatterns and their shapes [83,84]. Moreover, an optimum height of nanopillars could be identified yielding the highest osteogenic marker expression in MSCs [28].…”

Stem cell responses to nanotopography

“…The MSCs proliferated at the highest level on the square nanopatterned surface with respect to the others. Ca and P precipitation occurred only on the square geometric surfaces when MSCs were cultured without any osteogenic supplements, indicating that MSCs differentiated toward the osteoblastic lineage due to geometry …”

“…Ca and P precipitation occurred only on the square geometric surfaces when MSCs were cultured without any osteogenic supplements, indicating that MSCs differentiated toward the osteoblastic lineage due to geometry. 43 Wang et al used the M13 phage, a nontoxic nanofiberlike virus, to generate a virus-activated artificial ECM with constant ordered ridge/groove nanotopography but displaying different fibronectin-derived peptides. Ridge/groove nanotopography with the display of Arg-Gly-Asp and Pro-His-Ser-Arg-Asn induced the osteogenic differentiation of MSCs without any osteogenic supplements.…”

Effects of Nanomaterials on Synthesis and Degradation of the Extracellular Matrix

“…One study found that cells on square nanopillars showed greater spreading and diffusion as well as increased matrix deposition than on linear and triangular nanopillar surfaces. 192 However, precise control over the cross-sectional shape of nanopillars may be difficult due to limitations in fabrication techniques, and related studies are still very limited. Furthermore, the possible influence of factors such as the diameter and spacing of nanoprojections on ECM synthesis requires further investigation.…”