Low-temperature-processed biocompatible Ag-HAp nanoparticles with anti-biofilm efficacy for tissue engineering applications

Abstract

Biomaterial-associated infections are the major cause of implant failure and can also develop many years after implantation. Recent advances in nanotechnology and the development of new nano-materials have led to the design of anti-biofilm coatings on implant surfaces. In this study, the inhibition of biofilm formation on silver-doped hydroxyapatite (Ag-HAp) nanoparticles-coated glass slides is reported. Ag-HAp was synthesized using low-temperature-modified sol–gel method. The release of silver ions from the Ag-HAp reduced the adhesion and prevented formation of biofilms of Escherichia coli, Staphylococcus epidermidis and Pseudomonas aeruginosa when studied over a 10-day period. These coatings released an initial high amount of silver ions followed by a slow and gradual release facilitating sustained anti-biofilm activity. This initial high release of silver is beneficial for reducing bacterial adhesion which is the first step in the development of a biofilm. The biocompatibility of silver-doped hydroxyapatite coatings has also been confirmed. As success or failure of an implant depends on the balance between host tissue integration and bacterial colonization, the competitive growth between the mammalian and bacterial cells by inoculating E. coli into actively growing MG63 osteosarcoma cells on Ag-HAp coatings has been investigated. This could mimic the peri-operative contamination model. Ag-HAp-coated slides exhibit anti-biofilm activity over a period of 10 days, while supporting the growth of osteosarcoma cells (MG63). Co-culturing of MG63 cells with bacteria showed healthy growth of MG63 cells and no growth of bacteria. HAp control did not support growth of MG63 cells in the presence of bacteria.