Prevention of Adhesion and Surface Growth of Orthopedic Implant Microbial Infection by Surface Modification Using Antibiotics and Irradiated Hydroxyapatite

Abstract

Surface modification of orthopedic implants to eliminate and/or prevent microbial growth and adherence ability is a new strategy used in medical application. In this study, 52 pathogenic isolates were collected from orthopedic wound infection. Biofilm formation was quantitatively determined for biofilm producer isolates. The results revealed that isolates no. 8, 22, 34, 47, 49, 50 and 52 had the ability to produce a strong biofilm. While 19 and 6 isolates were moderately and weakly biofilm producing, respectively. The impact of gamma irradiation on microbial flora of hydroxyapatite (HAp) was investigated and it was noticed that a radiation dose at 25 kGy was effective and sufficient to reduce the counts to non-detectable levels. Characterization of HAp was carried out using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results indicated that no noticeable change was observed in the chemical composition of irradiated HAp. Evaluation of antimicrobial activity of HAp was performed against strong biofilm producer isolates. The results revealed that irradiation of HAp (100 mg/ml) increased its antimicrobial activity, compared to non-irradiated. Detection of adherence ability of tested strains on the surface of 316L SS chips uncoated and coated with irradiated HAp alone or combined with antimicrobial agents was performed. It was found that the adherence decreased after coating with irradiated HAp by only two log cycles while it was decreased by three log cycles after coating with HAp and antimicrobial agents.