In vivo and in vitro biological efficacy of double-layer coating of titanium with gelatin and calcium phosphate

Abstract

This paper presents a new type of surface modification of titanium to promote osseointegration. A double-layer coating was designed to endow titanium with enhanced osteoconductivity; a gelatin layer, that offers an environment for the attachment of osteoblast cells, was covalently bonded to the surface of titanium, after which a calcium phosphate layer composed of octacalcium phosphate and low-crystallinity hydroxyapatite was deposited onto specimens at 310K with the mediation of urease. Although it has been difficult to combine gelatin and calcium phosphate because there has never been an appropriate technique to do so, a newly developed technique employing urease has made possible to deposit calcium phosphate at 310 K. The calcium phosphate layer was approximately 20 to 30μm thick and adhered well to the titanium/gelatin substrate. The gelatin/calcium phosphate layer promoted the proliferation of osteoblast-like MC3T3-E1 cells and subsequent calcification. Additionally, an implant test in GK rats suggested that the layer may enhance the formation of new bone and new blood vessels. The surface modification presented herein may be a promising technique for dental and orthopedic implants. © 2012 The Ceramic Society of Japan.