Fabrics based on Cyclodextrin/Photosensitiser systems for Photodynamic Antimicrobial Therapy

In the development of new antibacterial therapeutic approaches to fight multidrug-resistant bacteria, photodynamic antimicrobial therapy (PAT) represents a well-known alternative to treat local infections caused by different microorganisms.1-3 Here we present a polypropylene (PP) fabric finished with citrate-hydroxypropyl-?CD polymer (PP-CD)4 entrapping the tetra-anionic 5,10,15,20-tetrakis(4-sulfonatophenyl)-21H,23H-porphine (TPPS) as photosensitizer eluiting fabric for PAT. The concept is based on host-guest complexation of porphyrin in the cavities of CDs immobilized on the PP fibers, followed by its sustained and controlled delivery in release medium and simultaneous photo-inactivation of microorganisms. Morphology of fabric was characterized by optical (OM) and scanning electron microscopies (SEM). Optical properties were investigated by UV-vis absorption, steady- and time-resolved fluorescence emission spectroscopy. X-ray Photoelectron Spectroscopy (XPS) and FT-IR revealed the surface chemical composition and the distribution map of the molecular components on the fabric, respectively. Direct 1O2 determination allowed to assess the potential photodynamic activity of the fabric. Release kinetics of TPPS in physiological conditions pointed out to the role of the CD cavity to control the TPPS elution. Transfer of TPPS from textile to colonies of Gram (+) S. aureus ATCC 29213 was ascertained by both microscopy and UV-vis extinction and fluorescence spectra which were acquired on bacterial cells microscopic images. Finally, photodynamic antimicrobial efficacy and anti-adhesive properties were established on porphyrin- treated cells after irradiation.