Antibacterial silk fibroin scaffolds with green synthesized silver nanoparticles for osteoblast proliferation and human mesenchymal stem cell differentiation.

The advance of antibiotic-resistant bacteria has generated countless new challenges in modern healthcare, which in turn has incited an improved attention towards the discovery of the new engineered antimicrobial techniques. This antibiotic resistance is also a major challenge in bone tissue engineering and the ideal means to overcome it is to promote tissue integration prior to bacterial adhesion, thus preventing colonization of certain bacterial species on the implant. The silk fibroin is a favorable biomaterial for bone tissue engineering, and silver nanoparticles (AgNPs) show antimicrobial activity against a large number of bacteria, including antibiotic-resistant strains, thus combined, these materials are good candidates for development of antibacterial scaffolds. While, silver nanoparticles have been extensively used as an antibacterial, its effect on stem cell differentiation is still not clear. We report here, a silk fibroin based bone tissue engineered scaffold with AgNPs having advanced antimicrobial properties, without compromising its cytocompatibility and stem cell differentiation potential. For this purpose, AgNPs were in situ synthesized using silk fibroin as reducing as well as stabilizing agent. The antimicrobial activity of silk fibroin films with AgNPs was evaluated against gram negative bacteria as well as antibiotic resistant bacteria and it was found to be effective against both. The cytocompatibility of these scaffolds was examined with fibroblast and osteoblast cells. Also, the effect of AgNPs present in films, on osteogenic differentiation potential of human mesenchymal stem cells was studied and it was observed that the presence of AgNPs at lower concentrations did not have any detrimental effect.