Enhancing corrosion resistance and biocompatibility of interconnected porous β-type Ti-24Nb-4Zr-8Sn alloy scaffold through alkaline treatment and type I collagen immobilization

We present a unique way of combining alkali treatment and natural cross-linker, procyanidin, to create submicron-porous structure (pore size 100–300 nm) and immobilize type I collagen on the surface of electron beam melted β-type Ti-24Nb-4Zr-8Sn (Ti2448) alloy scaffold with interconnected porosity. Scanning electron microscopy and transmission electron microscopy showed a hybrid layer, an outer submicron-porous layer and an inner dense layer, was formed on the interconnected Ti2448 alloy scaffold surface. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Sirius red staining analysis confirmed the collagen was successfully immobilized on the scaffold. The dense inner oxide layer mainly provided Ti2448 alloy scaffold with enhanced corrosion resistance. The Ti2448 alloy scaffolds, with and without surface treatments, were potentially non-cytotoxic; particularly, the type I collagen-immobilized Ti2448 alloy scaffold via procyanidin cross-linking showed better adhesion of human bone marrow mesenchymal stem cells. The proposed simple and unique surface treatment simultaneously enhances the corrosion resistance and cell adhesion of interconnected porous Ti2448 alloy scaffold without causing cytotoxicity and shows great potential for biomedical implant applications.