Reactive combinatorial synthesis and characterization of a gradient Ag–Ti oxide thin film with antibacterial properties. (1st January 2015)

• Record Type: Journal Article
• Authors: Unosson, Erik; Rodriguez, Daniel; Welch, Ken; Engqvist, Håkan
• Is Part Of: Acta biomaterialia. Volume 11(2015)
• Page Start: 503
• Page End: 510
• Publication Date: 2015-01-01
• Subjects: Combinatorial materials science -- Physical vapor deposition -- Antibacterial -- Silver -- Titanium; Biomedical materials -- Periodicals; 610.28
• DOI: 10.1016/j.actbio.2014.09.048
• Languages: English
• ISSNs: 1742-7061

Abstract

Graphical abstract: Abstract: The growing demand for orthopedic and dental implants has spurred researchers to develop multifunctional coatings, combining tissue integration with antibacterial features. A possible strategy to endow titanium (Ti) with antibacterial properties is by incorporating silver (Ag), but designing a structure with adequate Ag + release while maintaining biocompatibility has been shown difficult. To further explore the composition–structure–property relationships between Ag and Ti, and its effects against bacteria, this study utilized a combinatorial approach to manufacture and test a single sample containing a binary Ag–Ti oxide gradient. The sample, sputter-deposited in a reactive (O2 ) environment using a custom-built combinatorial physical vapor deposition system, was shown to be effective against Staphylococcus aureus with viability reductions ranging from 17 to above 99%, depending on the amount of Ag + released from its different parts. The Ag content along the gradient ranged from 35 to 62 wt.%, but it was found that structural properties such as varied porosity and degree of crystallinity, rather than the amount of incorporated Ag, governed the Ag + release and resulting antibacterial activity. The coating also demonstrated in vitro apatite-forming abilities, where structural variety along the sample was shown to alter the hydrophilic behavior, with the degree of hydroxyapatite deposition varying accordingly. By means of combinatorial synthesis, a single gradient sample was able to display intricate compositional and structural features affecting its biological response, which would otherwise require a series of coatings. The current findings suggest that future implant coatings incorporating Ag as an antibacterial agent could be structurally enhanced to better suit clinical requirements.