Stainless and titanium fibers as non-degradable three-dimensional scaffolds for bone reconstruction

Abstract

Stainless steel is used for various medical devices. Titanium is also widely used because of its tight bonding to bone tissue, namely osseointegration. The aim of the present study was to investigate the efficacy of three-dimensional stainless steel and titanium porous structure scaffolds by in vitro and in vivo experiments. Stainless steel and titanium fiber materials were designed as non-degradable metallic three-dimensional scaffolds with a three-dimensional porous structure for bone reconstruction. In one in vitro experiment, stainless steel and titanium disks were immersed in simulated body fluid. After immersion, a greater amount of hydroxyapatite precipitation was observed on titanium disks than on stainless steel disks. The crystallographic structure of precipitated hydroxyapatite was confirmed by the measurement of X-ray diffraction patterns. In another in vitro study, the adsorption behavior of fibronectin to stainless steel and titanium was monitored by the quartz crystal microbalance (QCM) method, which demonstrated more fibronectin adsorption onto titanium than onto stainless steel. In an in vivo experiment, three-dimensional stainless steel or titanium fibers were implanted into the cortical bone of the tibia of rabbits. Histological and histomorphometrical evaluation revealed a significantly greater amount of bone formation inside the porous area of the titanium fibers after 4 weeks of implantation. The present study also revealed better osteoconductivity of titanium than stainless steel. It is presumed that this was due to the differences in the characteristics of passive film between titanium and stainless steel. Titanium fibers are expected to be useful as a non-resorbable three-dimensional scaffold in bone reconstruction.