A comparative review on silk fibroin nanofibers encasing the silver nanoparticles as antimicrobial agents for wound healing applications

The development of multifunctional biomaterials for wound dressings, bandages, tissue scaffolds, etc., has received massive attention in the biomedical field in the last few years. The advanced progress in tissue engineering is the fabrication of smart biomaterials mimicking extracellular matrix (ECM) of human tissue, such as nanofibrous meshes with a micro and nanoporous structure. Silk fibroin (SF) nanofiber is an ideal candidate as a vehicle/substitute material for biomedical utilization due to its several unique properties, including high biocompatibility, biodegradability, and deficient inflammatory reactions. These characteristics make SF a favorable matrix for therapeutic agents. However, unmodified SF could be oxidized quickly, exhibit hydrophobicity, making it inappropriate for biological applications, and inclined to microbial attacks, lessening its applicability. Intensive research is going on to extend the capabilities of SF from hydrophobic material to hydrophilic, from the filament to film, sheet, and scaffolds, and even from soft material to super-rigid material. The researchers have traversed multiple approaches to remodel SF nanofibers to improve the utilization of SF. The threat of infections is inevitable when using SF as wound healing dressing elements or artificial grafts in tissue engineering applications. To confer antimicrobial property to SF, the use of silver nanoparticles and other silver composites is one of the strategies. Silver is a natural antimicrobial agent and has been used since ancient times. Researchers have incorporated silver in the SF nanofibers to impart antimicrobial properties and improve their applications. This review describes the extraction process of SF from silkworms using different methods and their comparative analysis. The electrospinning of SF nanofibers and the important parameters that need to be considered during the fabrication of electrospun SF nanofibers has also been discussed. Furthermore, this review has focused on the current progress in improvising SF nanofiber utilizing silver nanoparticles for antibacterial and wound healing applications.