Wool Keratin 3D Scaffolds with Light-Triggered Antimicrobial Activity.

Photo-activatable keratin sponges were prepared from protein aqueous solutions by freeze-drying method, followed by photo-functionalization with two different photosensitizers (PS): Azure A (AzA) and 5,10,15,20-tetrakis [4-(2-N,N,N-trimethylethylthio)-2,3,5,6-tetrafluorophenyl]porphyrin tetraiodide salt (TTFAP). The prepared sponges have a porosity of between 49% and 80% and a mean pore size in the 37 - 80 μm range. As compared to AzA, TTFAP interacts more strongly with the sponges as demonstrated by a lower PS release (6% vs 20%), a decreased swelling ratio (1.6 vs 7.4) and a slower biodegradation rate. Nevertheless, AzA loaded sponges showed the highest photo-activity, as also demonstrated by their higher anti-bactericidal activity towards both Gram-positive and Gram-negative bacteria. The obtained results suggest that the antimicrobial photodynamic effect can be finely triggered through a proper selection of the amount and type of photosensitizer, as well as through the irradiation time. Finally, all the prepared sponges support human fibroblast cells growth, while no significant cells viability impairment is observed upon light irradiation.