Nosocomial infections following implantation surgery are of great concern because of the possibility of implant failure, which requires removal of the infected implant, with the consequent reduction in the patient's quality of life and huge economic loss. In addition, the prevalence of antibiotic-resistant strains of bacteria is estimated to be responsible for thousands of deaths in the near future. At this point, the possibility of incorporating antibacterial properties into implants could reduce the prevalence of infections on their surface. That can be achieved by generating coatings on the surface of the biodegradable implants that control their degradation rate[1] while providing bactericidal properties. To avoid the antibiotic resistance, instead of classical antibiotics, different nanoparticles like Ag or Cu nanoparticles[2][3] can be added to the coatings to promote bacterial apoptosis.

In this work, hybrid silica sol-gel coatings were prepared and doped with different concentrations of silver nanoparticles (AgNPs) and silver nanofibers (AgNFs) to control the degradation rate of the AZ31 magnesium biodegradable alloy while providing antibacterial capacity. E. Coli and S. Aureus bacterial strains were inoculated on the surface of bare magnesium substrates and on the surface of samples treated with sol-gel coatings doped with different concentrations of silver nanoparticles.

Live/Dead Baclight Kit in combination with fluorescence microscopy, planktonic bacterial viability and inhibition halo assays show that AgNPs and AgNFs loaded sol-gels diminish bacterial viability for all silver nanoparticle concentrations, in contrast to the undoped sol-gel coating, where higher bacterial viability was observed. Thus, the use of these nanoparticles in the sol-gel coatings could contribute to the development of biodegradable magnesium implants with infection inhibitory power.