A novel antibacterial titania coating: Metal ion toxicity and in vitro surface colonization

Abstract

Postoperative implant-associated infection is still an unresolved and serious complication in modern surgery. Antibacterial and biocompatible surfaces could both reduce infection rates and promote tissue integration. In this respect, a comparative study of the antibacterial as well as the biocompatible potential of different metal ions in vitro is presented. The assays used were growth inhibition tests with different metal salts carried out with tissue cells and bacteria under corresponding culture conditions. Additionally, in vitro tests in direct surface contact with tissue cells and bacteria onto a novel copper containing sol-gel derived titanium dioxide coating (Cu-TiO2) and a fourfold Cu-TiO2 coating were performed. The values were compared to a non-filled titanium dioxide coating and standard Ti6Al4V alloy. SEM-investigations were performed to approve the results of the in vitro tests. Among Ag+, Zn2+, Co2+, Al3+ and Hg2+, the growth inhibition tests revealed an outstanding position of copper ions as antibacterial but nevertheless bio-tolerant additive. These results were affirmed by the cell tests in direct surface contact and SEM-investigations, where best cell growth was found on the Cu-TiO2 coatings. Highest antibacterial properties with a tolerable cytocompatibility could be observed on the fourfold Cu-TiO2 coatings. Consequently, surfaces with custom-tailored antibacterial properties may be established and could be of particular interest in revision and tumor arthroplasty.

Antibacterial and Biocompatible Titanium-Copper Oxide Coating May Be a Potential Strategy to Reduce Periprosthetic Infection: An In Vitro Study

“…Antibacterial Activity Using a previously described method [13,16], discs were submerged in separate wells containing 2 mL Roswell Park Fig. 1 This schematic drawing shows the characteristics of the closed-field unbalanced magnetron sputtering system used for TiCuO coating depositions.…”

“…Copper is essential for several cellular enzymatic reactions and plays an important role in hydrogen peroxide (H 2 O 2 ) and highly toxic hydroxyl radical (•OH) generation within phagocytes [2,14,30,34]. This makes copper an interesting material for coating metal implants as a way to prevent periprosthetic infection, especially when considering that copper ions have been shown to have superior antibacterial performance while maintaining biocompatibility in vitro compared with silver, zinc, cobalt, aluminum, and mercury ions [16]. This pilot study explores the value of a thin film of titanium-copper oxide (TiCuO) by describing its antibacterial effect, cytotoxicity, and copper ion elution pattern in vitro.…”

CORR Insights®: Antibacterial and Biocompatible Titanium-Copper Oxide Coating May Be a Potential Strategy to Reduce Periprosthetic Infection: An In Vitro Study

“…In fact, the US Environmental Protection Agency approved hundreds of such alloys for use on touch surfaces, such as door knobs, push plates, and railings. Interestingly, few studies have worked to extend the use of copper alloys to the surfaces of arthroplasty implants [3][4][5]. In this paper, Narambuena and colleagues have demonstrated as a ''proof-ofconcept'' that coating a titanium alloy with a thin film of titanium-copper oxide does provide antibacterial properties, with minimal osteoblast cellline toxicity.…”

Comparison of HIPIMS sputtered Ag- and Cu-surfaces leading to accelerated bacterial inactivation in the dark

“…This value is lower compared to the Cu-release from the Cu-HIPIMS sputtered samples of tõ 18 ppb Cu/cm 2 at the end of the 8th cycle. In both cases the amounts of Cu are not to be cytotoxic to mammalian cells [17,19,38] and proceed through an oligodynamic effect [23] being in principle possible to be used to induce bacterial inactivation on implants in a way that it is not toxic to human health. The antibacterial effects of Cu-nanoparticulate films shown in Fig.…”

“…Since the effect of Cu-ions is extremely toxic to bacteria at very low concentrations (ppb range) many formulations of surfaces and implants coated with Cu present a higher cytocompatibility than Ag for mammalian cells. Cu is a metabolizable agent [17] compared to Ag that stays in the body after ingestion increasing the Ag-serum levels [18]. The antibacterial effects of Cu-TiO 2 coatings against MRSA have been reported by Cu-TiO 2 coating thickness, the layers on medical devices showing high mechanical stability without cracks in the coating [19].…”