Effects of Composition on Antibacterial Properties of Suspension Plasma-Sprayed Hydroxyapatite / Titania Coating

Abstract

This study aims at revealing the effect on composition on antibacterial properties of hydroxyapatite/titania composite coating deposited by suspension plasma spray. HAp/TiO₂ coating is used for biomedical application especially for antibacterial coating. However, in order to widely use it safely, visible-light sensitivity is important. TiO₂ coating is not effectively activated by visible-light, therefore Suspension Plasma Spray (SPS) system have been used to adjust crystallographic phases of TiO₂ in order to provide them visible-light sensitivity. Prior to deposition, substrates were grit blasted, cleaned ultrasonically and heated to enhance adhesion strength. Microstructure of coating of different composition was then characterized using XRD & RAMAN to identify its crystal structure. All results demonstrated that SPS could transform Ti₂O₃ into TiO₂ with mixed phases. Particularly, XRD data identified Ti₄O₇ & Ti₃O₅ phases, which usually show photocatalytic activity due to oxygen vacancies. Antibacterial test using bacteria is also conducted, and the optimized composition was determined. SPS could produce enhanced antibacterial coating of HAp/Titania composite.