Femtosecond laser nano/micro patterning of titanium influences mesenchymal stem cell adhesion and commitment

Abstract

Surface improvement of implants is essential for achieving a fast osseo-integration. Technically, the creation of a precise pattern on a titanium alloy surface is challenging. Here, the femtosecond laser was chosen as an innovative technology for texturing with accuracy a nano-micro topography. By adjusting the laser parameters, three biomimetic textures were fabricated on the titanium surface: micropits with nano-ripples in the pits, micropits with nano-ripples around the pits, and a texture with only nano-ripples. Mesenchymal stem cells (MSCs, C3H10T1/2) grown on these surfaces displayed altered morphometric parameters, and modified their focal adhesions in term of number, size, and distribution depending on surface type. These results indicate that the MSCs perceived subtle differences in topography. Dynamic analyses of early cellular events showed a higher speed of spreading on all the textured surfaces as opposed to the polished titanium. Concerning commitment, all the laser-treated surfaces strongly inhibited the expression of adipogenic-related genes (PPARϒ2, C/EBPα) and up-regulated the expression of osteoblastic-related genes (RUNX2, osteocalcin). Interestingly, the combination of micropits to nano-ripples enhanced their osteogenic potential as seen by a twofold increase in osteocalcin mRNA. Alkaline phosphatase activity was increased on all the textured surfaces, and lipid production was down-regulated. The functionalization of metallic surfaces by this high-resolution process will help us understand the MSCs' interactions with substrates for the development of textured implants with predictable tissue integrative properties.

Surface micro- and nano-texturing of stainless steel by femtosecond laser for the control of cell migration

“…observed an improvement of endothelial and bone marrow mesenchymal stem cells on fs nano-textured 316L steel, showing that femtosecond surface texturing could improve osseointegration. Dumas et al 26. proved the ability of fs-structured surfaces to increase osteogenesis and inhibit adipogenesis of MSCs.…”

Effect of patterned electrospun hierarchical structures on alignment and differentiation of mesenchymal stem cells: Biomimicking bone

“…Micropatterning is found to change the cellular niche and hence the fate of MSCs. A double texture of micro and nano features have shown a commitment of cells to osteogenic lineages (Dumas et al, ). ALP staining results of our study clearly shows that the micro pattern as well as the nano scale surface structure affects the osteogenic differentiation of cells.…”

Electrospun Fibers for Recruitment and Differentiation of Stem Cells in Regenerative Medicine

“…Aligned electrospun fibers showed an increased differentiation of MSCs as compared to cross‐aligned fibers. The gap junctions are said to align along the pattern, and the polarization effect of gap junctions has an effect on the differentiation of cells . A novel multilayered aligned Poly(ϵ‐caprolactone) (PCL) electrospun scaffolds showed an increased cellular infiltration, development of tendon ECM and differentiation of MSCs into tendon fibroblasts as compared to non‐aligned fibers (Figure A) .…”