Functional and biocompatibility of orthopaedic metal implant coated with silver

Abstract

The prevalence of orthopaedic implant-related infections remains high. Bacterial colonisation and biofilm adhesion on the implant can cause infection at the underlying bone and surrounding tissues. The management of this incidence poses major challenges in orthopaedic. Although several conventional strategies were taken to control the incidence, none of them is effective in all cases. The application of orthopaedic metal implant coated with silver composite (OMICS) has been suggested as an alternative to reduce or prevent implant-related infections. This study aimed to (1) determine the antibacterial properties of OMICS against Staphylococcus aureus (S. aureus); (2) evaluate the toxicology effects of OMICS on in vitro cellular and in vivo animal models; (3) perform and validate surgical approach using an open fracture model that expose bone to the environment for six hours to induce osteomyelitis in the New Zealand White (NZW) rabbits; and (4) evaluate the efficacy of OMICS as antibacterial agent and its biocompatibility in animal models. The silver composite was extracted from OMICS using two different immersion techniques, namely water bath and magnetic stirrer. The potential of OMICS as an antibacterial agent against S. aureus was investigated. The toxicity and biocompatibility studies were conducted in an accredited testing laboratory operating in accordance with the ISO 10993 to validate the biosafety aspect and ISO 17025 to validate the biocompatibility of OMICS. The OMICS were implanted in NZW rabbits after six hours of tibial bone exposure following validation of the open wound surgical approach. The rabbits were euthanised at week three and week six post-operatively. The OMICS-implanted tibia was excised en bloc and evaluated through post-mortem of microbial assessment for signs of infection as well as the post-mortem of radiographic evaluations, gross inspection and histological analysis for quality implantation assessment. The results showed that the variance for OMICS silver release extraction was significant with value F (1,10) = 4.996, p = 0.034, η^2 p = 0.285. As for the analysis variance of anti-microbial, it showed that the effect of silver release was significant with value F (1,10) = 11.071, p = 0.003, η^2 p = 0.356. The OMICS group halted the S. aureus growth “significantly” better than the control group indicative of antibacterial properties of the OMICS against the bacteria. The OMICS does not produce any mutagenic and toxicity effects after exposure in both cellular and tissue level. Besides, OMICS did not induce skin sensitisation after exposed to animal models. The post-mortem of the microbial assessment showed no signs of infection isolated at week six. The post-mortem of radiographic evaluations, gross inspection and histological analysis showed there is good integration between bone and OMICS implant at surrounding tissue. The OMICS is thus shown to be effective to reduce infection during implantation. In conclusion, the above results showed that OMICS is biocompatible and holds potential to reduce infection during implantation.