Antibacterial coating made of strongly adhered nanosilver to titania nanotubes for dental implants

Abstract

Objectives: An antibacterial and biocompatible coating on Ti-6Al-4V alloy was synthesised. A method of making the antibacterial effect long term, without any acute release of silver from a dental implant, on insertion was devised.Methods: Titania nanotubes were grown on Ti-6Al-4V alloy using anodisation in the presence of phosphate and fluoride ions. Following alkali treatment of the latter surface, silver nanoparticles were chemically reduced on the nanotubes. The latter surface was then characterised using high resolution electron microscopy (SEM) in association with energy dispersive X-Ray Spectroscopy (EDS) and Raman Spectroscopy. A silver release test was performed. Following a toxicity test in the presence of Human Osteoblast Cells, the biocompatibility of the coating would be assessed.Results: Initially, titania nanotubes with diameter of c. 100 nm were formed following the deposition of silver nanoparticles (10-25nm) on the outer and inner walls. The chemical structure of the nanoparticles was confirmed by Raman Spectroscopy and EDS. The results also highlighted the different bonding attaching the nanosilver to the walls. Subsequently a very low amount of silver was released from the coating during the beginning of the silver release test confirming a good adherence between the nanosilver and the nanotubes. The low leaching was expected to reduce the toxicity of the implant in general and it was confirmed by growth of human osteoblast cells on the coating.Conclusions: The strong adhesion of silver nanoparticles validated the fact that the coating on titanium alloy can prevent an acute release of silver as such having the possibility of having a long term antibacterial effects. This work gave rise to a novel method of synthesising an antibacterial coating for dental implants.