Wool Keratin 3D Scaffolds with Light-Triggered Antimicrobial Activity

Photoactivatable keratin sponges were prepared from protein aqueous solutions by the freeze-drying method, followed by photofunctionalization 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 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 photoactivity, as also demonstrated by their higher antibactericidal activity toward 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 pr...