Biomaterials based on porphyrinoid/cyclodextrin assemblies: from hybrids to composites with photoantimicrobial action

The rapid rise in antimicrobial resistance (AMR) demands innovative and broad-spectrum antimicrobial solutions capable of inactivating pathogens without favouring resistance development. Within our ongoing research on photosensitising supramolecular assemblies, here we present various novel biomaterials based on cyclodextrin and porphyrinoids to fight infections. In particular, we discuss assemblies of (Zn(II)- meso Tetra (N-methyl-4- pyridyl)-21H,23H-porphyrin Tetratosylate (ZnT4)) with the trade sulfobutylether-β-cyclodextrin (Captisol®) that were incorporated in a fast-resorbable hydrogel composed of hyaluronic acid grafted with poly-lactic acid (HAPLA) named DAC®. Moreover, we present assemblies of ZnT4 with a polymeric sulfobutylether-β- cyclodextrin and a nanohybrid of meso-tetrakis(N-methylpyridinium-4-yl)porphine (H2T4) with silver nanoparticles (AgNPs). AgNPs were produced through the reduction of silver nitrate assisted by a cyclodextrin based polymer bearing citrate functionalities which also acts as stabilizing agent of NPs. Finally, a biodegradable and microporous composite membrane of chitosan (CHT) and porphyrin was developed as a potential patch for the treatment of skin diseases. The composite membrane was developed by incorporating in the dispersion of CHT the Captisol®/H2T4 photosensitizing nanosystem. All of these biomaterials were fully characterized by spectroscopic and morphological techniques and demonstrated significant photobactericidal activity against a plethora of bacterial strains, including in some case biofilm. Altogether, in vitro studies elucidated the photoantimicrobial efficacy of these photosensitizing biomaterials incorporating cyclodextrin/porphyrinoids assemblies.