Comparison of Selective Laser Melted Titanium and Magnesium Implants Coated with PCL

TL;DR

This study compares magnesium and titanium implants coated with PCL to evaluate their biocompatibility and corrosion resistance for bone implants.

Contribution

The novel use of selective laser melting to produce biocompatible, corrosion-resistant magnesium implants coated with PCL is presented.

Findings

PCL coating significantly reduced the corrosion rate of magnesium implants.

SLM-produced magnesium with PCL coating showed good biocompatibility with murine osteoblasts.

Porous structures from SLM improved osseointegration potential.

Abstract

Degradable implant material for bone remodeling that corresponds to the physiological stability of bone has still not been developed. Promising degradable materials with good mechanical properties are magnesium and magnesium alloys. However, excessive gas production due to corrosion can lower the biocompatibility. In the present study we used the polymer coating polycaprolactone (PCL), intended to lower the corrosion rate of magnesium. Additionally, improvement of implant geometry can increase bone remodeling. Porous structures are known to support vessel ingrowth and thus increase osseointegration. With the selective laser melting (SLM) process, defined open porous structures can be created. Recently, highly reactive magnesium has also been processed by SLM. We performed studies with a flat magnesium layer and with porous magnesium implants coated with polymers. The SLM produced magnesium was compared with the titanium alloy TiAl6V4, as titanium is already established for the SLM-process. For testing the biocompatibility, we used primary murine osteoblasts. Results showed a reduced corrosion rate and good biocompatibility of the SLM produced magnesium with PCL coating.

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