On the Use of Functionally Graded Materials to Differentiate the Effects of Surface Severe Plastic Deformation, Roughness and Chemical Composition on Cell Proliferation

Laurent Weiss,Pascal Laheurte,Marc Novelli,Thierry Grosdidier,Yaël Nessler

doi:10.3390/met9121344

Abstract

Additive manufacturing allows the manufacture of parts made of functionally graded materials (FGM) with a chemical gradient. This research work underlines that the use of FGM makes it possible to study mechanical, microstructural or biological characteristics while minimizing the number of required samples. The application of severe plastic deformation (SPD) by surface mechanical attrition treatment (SMAT) on FGM brings new insights on a major question in this field: which is the most important parameter between roughness, chemistry and microstructure modification on biocompatibility? Our study demonstrates that roughness has a large impact on adhesion while microstructure refinement plays a key role during the early stage of proliferation. After several days, chemistry is the main parameter that holds sway in the proliferation stage. With this respect, we also show that niobium has a much better biocompatibility than molybdenum when alloyed with titanium.

Highlights

IntroductionAmong all the techniques allowing the improvement of the cells adhesion and proliferation, severe plastic deformation (SPD) of the material has been studied for about one decade and, since been the subject of several investigations
Improving the biocompatibility of titanium and titanium alloy prostheses is a major challenge for the biomedical industry and has been the subject of much scientific interest in recent years [1,2].Among all the techniques allowing the improvement of the cells adhesion and proliferation, severe plastic deformation (SPD) of the material has been studied for about one decade and, since been the subject of several investigations
The results have shown that the refinement of the microstructure by equal-channel angular pressing (ECAP) leads to a better wettability and a better adhesion and proliferation of fibroblasts after two and five days

Summary

Introduction

Among all the techniques allowing the improvement of the cells adhesion and proliferation, severe plastic deformation (SPD) of the material has been studied for about one decade and, since been the subject of several investigations. The first biocompatibility study on pure titanium deformed by SPD was carried out by Kim et al in 2007 [3]. The results have shown that the refinement of the microstructure by equal-channel angular pressing (ECAP) leads to a better wettability and a better adhesion and proliferation of fibroblasts after two and five days. Other teams have shown that ECAP leads to a better proliferation of mouse fibroblasts after 72 h [5] and a better adhesion of human mesenchymal stem cells (MSCs) [6].

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