Evaluation of Antibacterial and Cytotoxic Properties of a Fluorinated Diamond-Like Carbon Coating for the Development of Antibacterial Medical Implants.

Katsutaka Yonezawa,Masahito Kawaguchi,Makoto Taki,Ayumi Kaneuji,Shinobu Oda,Norio Kawahara,Yoshitsugu Iinuma,Toru Ichiseki,Kae Kawamura,Kazuhiro Shintani

doi:10.3390/antibiotics9080495

Abstract

Peri-implant infection is a serious complication in surgical procedures involving implants. We conducted an in vitro study to determine whether the use of a fluorinated diamond-like carbon (F-DLC) coating on a titanium alloy surface can prevent peri-implant infection. After applying the F-DLC, we evaluated its antibacterial and cytotoxic properties. The coating groups, containing controlled fluorine concentrations of 5.44%, 17.43%, 24.09%, and 30%, were examined for the presence of Staphylococcus aureus and Escherichia coli according to ISO 22196 for the measurement of antibacterial activity on plastics and other nonporous surfaces. Biological toxicity was evaluated using Chinese hamster V79 cells according to ISO 10993-5 for the biological evaluation of medical devices. In the control group, populations of S. aureus and E. coli substantially increased from 2.4 × 104 to (1.45 ± 1.11) × 106 colony-forming units (CFUs) and from 2.54 × 104 to (4.04 ± 0.44) × 106 CFUs, respectively. However, no bacteria colonies were detected in any F-DLC group with a fluorine concentration of ≥ 17.43%. In the biological toxicity study, an F-DLC coating with a fluorine concentration of 30% showed a colony formation rate of 105.8 ± 24.1%, which did not differ significantly from the colony formation rate of 107.5 ± 31.1% in the nontoxic control group. An F-DLC coating on titanium alloy discs showed excellent in vitro antibacterial activity with no biological toxicity.

Highlights

In the study we report here, we focused on a fluorinated diamond-like carbon (F-DLC) coating
In examining the minimum bacterial growth-inhibitory concentration of fluorine, we found no antibacterial properties at a fluorine concentration of 5.44%, and we found that neither S. aureus nor E. coli showed colony growth when the concentration was ≥17.46%
S. aureus and E. coli, respectively, showing a colony formation rate of 105.8% on biological toxicity tests. These results indicate that an F-DLC coating and an Ag-HA coating impart comparable levels of antibacterial activity, but the former is associated with no cytotoxicity

Summary

Introduction

Implants, such as artificial joints and internal fixation materials, are routinely used in many operations, and postoperative peri-implant infections are the most serious complications.The incidence of postoperative bone and joint infections has been reported to be 0.6%–11.9% for spine surgery [1,2,3] and 0.2%–3.8% for primary arthroplasty [4,5,6,7,8,9,10,11,12,13], and even higher incidence rates, such as0.5%–17.3%, have been reported for revision arthroplasty [4,10,12]. Implants, such as artificial joints and internal fixation materials, are routinely used in many operations, and postoperative peri-implant infections are the most serious complications. The incidence of postoperative bone and joint infections has been reported to be 0.6%–11.9% for spine surgery [1,2,3] and 0.2%–3.8% for primary arthroplasty [4,5,6,7,8,9,10,11,12,13], and even higher incidence rates, such as. 0.5%–17.3%, have been reported for revision arthroplasty [4,10,12].

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