Atomic layer deposition of nano-TiO 2 thin films with enhanced biocompatibility and antimicrobial activity for orthopedic implants

• Published in: International journal of nanomedicine Vol. 12; pp. 8711 - 8723
• Main Authors: Liu, Luting, Bhatia, Ritwik, Webster, Thomas J
• Format: Journal Article
• Language: English
• Published: New Zealand 01.12.2017
• Subjects: Adsorption; Anti-Infective Agents - chemistry; Anti-Infective Agents - pharmacology; Coated Materials, Biocompatible - chemistry; Escherichia coli - drug effects; Humans; Materials Testing - methods; Methicillin-Resistant Staphylococcus aureus - drug effects; Nanostructures - chemistry; Nanotechnology - methods; Osteoblasts - cytology; Osteoblasts - drug effects; Prostheses and Implants; Staphylococcus aureus - drug effects; Surface Properties; Titanium - chemistry; Titanium - pharmacology; nanostructure; titanium dioxide; atomic layer deposition; fibroblast; antimicrobial activity; osteoblast
• ISSN: 1178-2013; 1178-2013
• DOI: 10.2147/IJN.S148065

Titanium (Ti) and its alloys have been extensively used as implant materials in orthopedic applications. Nevertheless, implants may fail due to a lack of osseointegration and/or infection. The aim of this in vitro study was to endow an implant surface with favorable biological properties by the dual modification of surface chemistry and nanostructured topography. The application of a nanostructured titanium dioxide (TiO ) coating on Ti-based implants has been proposed as a potential way to enhance tissue-implant interactions while inhibiting bacterial colonization simultaneously due to its chemical stability, biocompatibility, and antimicrobial properties. In this paper, temperature-controlled atomic layer deposition (ALD) was introduced for the first time to provide unique nanostructured TiO coatings on Ti substrates. The effect of nano-TiO coatings with different morphology and structure on human osteoblast and fibroblast functions and bacterial activities was investigated. In vitro results indicated that the TiO coating stimulated osteoblast adhesion and proliferation while suppressing fibroblast adhesion and proliferation compared to uncoated materials. In addition, the introduction of nano-TiO coatings was shown to inhibit gram-positive bacteria ( ), gram-negative bacteria ( ), and antibiotic-resistant bacteria (methicillin-resistant ), all without resorting to the use of antibiotics. Our results suggest that the increase in nanoscale roughness and greater surface hydrophilicity (surface energy) together could contribute to increased protein adsorption selectively, which may affect the cellular and bacterial activities. It was found that ALD-grown TiO -coated samples with a moderate surface energy at 38.79 mJ/m showed relatively promising antibacterial properties and desirable cellular functions. The ALD technique provides a novel and effective strategy to produce TiO coatings with delicate control of surface nanotopography and surface energy to enhance the interfacial biocompatibility and mitigate bacterial infection, and could potentially be used for improving numerous orthopedic implants.