Development of scaffolds composed of electrospun wool keratin subjected to gold deposition to enhance antibacterial performances for biomedical purposes

In biomedical applications, one of the current challenges is to develop alternative methods to traditional therapeutic approaches that focus on bio-based materials. The recovery and valorization of biopolymers derived from low-cost and renewable sources represents an important strategy for human and environmental well-being. Keratin, a fibrous protein, has gained attention for its abundance: it is a constituent of humans and animals, in particular wool fibres. Wool keratin is biodegradable, biocompatible, and bioresorbable. Additionally, it possesses interesting features that make it a valid candidate for biomedical employment, such as not inducing inflammatory and immunogenic responses. The scope of the present work is to produce scaffolds that mimic the porous structure of tissue’s extracellular matrix, endowed with antibacterial activity. To achieve these goals, the electrospinning technique is used to generate keratin nanofibres. The resulting wool keratin-based membranes are subjected to gold deposition to impart relevant antibacterial properties. The gold deposition is performed using three different modalities: sputtering for 30 seconds, sputtering for 60 seconds and sputtering for 5 seconds followed by wet chemical synthesis. The specimens have been characterized by spectroscopy, wettability, and mechanical properties, while their antibacterial performance has been tested against Staphylococcus aureus and Escherichia coli bacterial strains. Preliminary data on the antibacterial properties of keratin nanofibres produced by wet synthesis and with gold nanoparticles sputtered for 5 seconds indicate that these appear to be the optimal conditions for obtaining a scaffold with a promising antibacterial effect. Notwithstanding the fact that preliminary data demonstrate a reduction in both bacterial strains after one hour of contact, further studies are required in order to provide a more comprehensive evaluation of the antibacterial properties. These findings suggest that electrospun keratin-based scaffolds can play a significant role in the biomedical sector, paving the way for future investigations, such as cellular biocompatibility and antibacterial studies.