Generation and characterisation of gallium titanate surfaces through hydrothermal ion-exchange processes

Wadge, Matthew D ORCID: https://orcid.org/0000-0002-5157-507X, Stuart, Bryan W, Thomas, Kathryn G and Grant, David M ORCID: https://orcid.org/0000-0002-6786-7720 (2018) Generation and characterisation of gallium titanate surfaces through hydrothermal ion-exchange processes. Materials and Design, 155. pp. 264-277. ISSN 0264-1275

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Abstract

Infection negation and biofilm prevention are necessary developments needed for implant materials. Furthermore, an increase in publications regarding gallium (Ga) as an antimicrobial ion has resulted in bacterial-inhibitory surfaces incorporating gallium as opposed to silver (Ag). The authors present the production of novel gallium titanate surfaces through hydrothermal ion-exchange reactions. Commercially-pure Ti (S0: Cp-Ti) was initially suspended in NaOH solutions to obtain sodium titanate (S1: Na2TiO3) layers ca. 0.5–1 μm in depth (2.4 at.% Na). Subsequent suspension in Ga(NO3)3 (S2: Ga2(TiO3)3), and post-heat-treatment at 700 °C (S3: Ga2(TiO3)3-HT), generated gallium titanate layers (9.4 and 4.1 at.% Ga, respectively). For the first time, RHEED analysis of gallium titanate layers was conducted and demonstrated titanate formation. Degradation studies in DMEM showed S2: Ga2(TiO3)3 released more Ga compared to S3: Ga2(TiO3)3-HT (2.76 vs. 0.68 ppm) over 168 h. Furthermore, deposition of Ca/P in a Ca:P ratio of 1.71 and 1.34, on S2: Ga2(TiO3)3 and S3: Ga2(TiO3)3-HT, respectively, over 168 h was seen. However, the study failed to replicate the antimicrobial effect presented by Yamaguchi who utilised A. baumannii, compared to S. aureus used presently. The authors feel a full antimicrobial study is required to assess gallium titanate as a candidate antimicrobial surface.