Proliferation and osteogenic differentiation of rat BMSCs on a novel Ti/SiC metal matrix nanocomposite modified by friction stir processing.

Chenyuan Zhu,Liqiang Wang,Fuqiang Zhang,Yuting Lv,Haixin Qian,Chao Qian,Ting Jiao

doi:10.1038/srep38875

Chenyuan Zhu, Liqiang Wang + Show 5 more

Open Access

https://doi.org/10.1038/srep38875

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Abstract

The aims of this study were to fabricate a novel titanium/silicon carbide (Ti/SiC) metal matrix nanocomposite (MMNC) by friction stir processing (FSP) and to investigate its microstructure and mechanical properties. In addition, the adhesion, proliferation and osteogenic differentiation of rat bone marrow stromal cells (BMSCs) on the nanocomposite surface were investigated. The MMNC microstructure was observed by both scanning and transmission electron microscopy. Mechanical properties were characterized by nanoindentation and Vickers hardness testing. Integrin β1 immunofluorescence, cell adhesion, and MTT assays were used to evaluate the effects of the nanocomposite on cell adhesion and proliferation. Osteogenic and angiogenic differentiation were evaluated by alkaline phosphatase (ALP) staining, ALP activity, PCR and osteocalcin immunofluorescence. The observed microstructures and mechanical properties clearly indicated that FSP is a very effective technique for modifying Ti/SiC MMNC to contain uniformly distributed nanoparticles. In the interiors of recrystallized grains, characteristics including twins, fine recrystallized grains, and dislocations formed concurrently. Adhesion, proliferation, and osteogenic and angiogenic differentiation of rat BMSCs were all enhanced on the novel Ti/SiC MMNC surface. In conclusion, nanocomposites modified using FSP technology not only have superior mechanical properties under stress-bearing conditions but also provide improved surface and physicochemical properties for cell attachment and osseointegration.

Highlights

The microstructures of the Friction stir processing (FSP) samples often consisted of four primary zones: the base metal (BM), the heat-affected zone (HAZ), the thermomechanically affected zone, and the SZ38,46
Compared to the FSP-1 group, the FSP-2 group exhibited a higher density of silicon carbide (SiC) particles
Compared with the base material, the FSP surfaces led to the upregulation of all the examined mRNAs, RUNX2, OSX, and OCN, as well as the angiogenic factors vascular endothelial growth factor (VEGF), HIF-1αand ANG-1. These results suggest that the Ti/SiC metal matrix nanocomposite (MMNC) surface modified by FSP exerted robust positive effects on the later stages of osteogenic differentiation and the stages of vascularization

Summary

Introduction

A biomaterial must improve surface and physicochemical properties to promote cell attachment and osseointegration and possess superior mechanical properties for certain load-bearing conditions. Nanocomposites with enhanced mechanical properties that could improve bone tissue regeneration are attractive for biomedical applications[36,37]. The surface nanocomposites produced by the FSP technique exhibit excellent bonding with substrate, conferring superior mechanical properties[38]. Few studies have examined the effects of novel MMNC surfaces modified by FSP on cell proliferation and osteogenic differentiation. We hypothesize that the novel nanograined surface created by FSP promotes cell adhesion and proliferation and leads to effective integration of bioimplants while providing stable physical and mechanical properties. This study aimed to fabricate a novel Ti/SiC MMNC using FSP and to investigate its microstructure and mechanical properties. The proliferation and osteogenic differentiation of rat bone marrow stromal cells (BMSCs) on the sample surface were investigated

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