Microstructure of Selective Laser Melted Titanium Lattices and In Vitro Cell Behaviour

Abstract

Selective laser melting (SLM) is a metal additive manufacturing technology that allows the fabrication of complex near-net-shape titanium parts. Among possible applications, titanium is important for the biomedical sector, in particular for orthopaedics due to its low elastic modulus, biocompatibility, high mechanical strength and corrosion resistance. Several studies show the structural properties and mechanical behaviour of titanium lattices that in parallel exhibited the porosity, mechanical strength and elastic modulus of trabecular bone. However, less attention has been devoted to study the biological response to titanium parts fabricated by SLM. Therefore, this work aimed to fabricate commercially pure titanium lattices by SLM and study the behaviour of bone-forming cells cultured on the lattices. The results show that Saos-2 osteoblast-like cells proliferated and covered the entire available surface of the titanium lattices becoming confluent and quiescent. The activity of alkaline phosphatase and the production of extracellular calcium deposits confirmed the growth of viable and mature osteoblasts. The cytocompatibility of the titanium lattices is an additional advantage that adds to the possibility to mimic the porosity and mechanical properties of bone by computer-aided design and subsequently implement the lattice fabrication by SLM, fitting the requirements of individual patients and, consequently, offering a broad range of new bone repair alternatives in orthopaedics. Keywords: selective laser melting, titanium, microstructure, osteoblast, cytocompatibility.Selective laser melting (SLM) is a metal additive manufacturing technology that allows the fabrication of complex near-net-shape titanium parts. Among possible applications, titanium is important for the biomedical sector, in particular for orthopaedics due to its low elastic modulus, biocompatibility, high mechanical strength and corrosion resistance. Several studies show the structural properties and mechanical behaviour of titanium lattices that in parallel exhibited the porosity, mechanical strength and elastic modulus of trabecular bone. However, less attention has been devoted to study the biological response to titanium parts fabricated by SLM. Therefore, this work aimed to fabricate commercially pure titanium lattices by SLM and study the behaviour of bone-forming cells cultured on the lattices. The results show that Saos-2 osteoblast-like cells proliferated and covered the entire available surface of the titanium lattices becoming confluent and quiescent. The activity of alkaline phosphatase and the production of extracellular calcium deposits confirmed the growth of viable and mature osteoblasts. The cytocompatibility of the titanium lattices is an additional advantage that adds to the possibility to mimic the porosity and mechanical properties of bone by computer-aided design and subsequently implement the lattice fabrication by SLM, fitting the requirements of individual patients and, consequently, offering a broad range of new bone repair alternatives in orthopaedics. Keywords: selective laser melting, titanium, microstructure, osteoblast, cytocompatibility.