A Polycarboxylic Acid-Cyclodextrin/Porphyrin Fabric as Photosensitiser Eluiting System for Photodynamic Antimicrobial Therapy

Currently, since the increasing of multidrug-resistant bacteria, due to the overrated antibiotics utilize, research efforts are addresses on new antibacterial therapeutic approaches. Photodynamic antimicrobial therapy (PAT) is a well-known choice to treat local infection caused by different microorganisms such as Gram (+) and Gram (-) bacteria, viruses, fungi and protozoa. PAT plays a central role in the treatment of surface wounds, burns, abscesses, oral sites and the middle ear infections. Native and hydroxypropylated cyclodextrins (HP?CD) have been successfully grafted to textiles based on natural and synthetic fibers by using polycarboxylic acids (PCA) as crosslinking agents. The concept is based on host-guest complexation of different typology of drug molecules in the cavities of CDs immobilized on the fabric, followed by its sustained and controlled delivery in release medium. A relevant advantage of this concept is its versatility, as it is compatible with a wide range of antibiotics offering good potential for PAT. Here we present a polypropylene (Poly) fabric finished with citrate-hydroxypropyl-?-CD polymer (CTR-CD) entrapping the tetraanionic 5,10,15,20-tetrakis(4 sulfonatophenyl)-21H,23H-porphine (TPPS) as photosensitizer. To the best of our knowledge, this CD/TPPS finished fabric represents a novel eluting device to efficiently deliver TPPS to bacterial cells, which can be photo-inactivated upon irradiation. Morphology of fabric was characterized by optical (OM) and scanning electron microscopy (SEM). Optical properties were investigated by UV-Vis absorption, and steady- and time-resolved fluorescence emission spectroscopy. XPS and FT-IR revealed the chemical composition and the distribution map of the molecular components on the fabric, respectively. Direct 1O2 determination allowed evaluating the potential photodynamic activity of fabric. Release kinetics of TPPS in PBS (pH=7.4) pointed out to the role of the CD cavity to control the drug eluition from fabric. Transfer of TPPS from PolyCTR-CD/TPPS to colonies of Gram (+) S. aureus ATCC 29213 was carried out and the presence of TPPS in the bacterial cells was confirmed by UV-Vis extinction and fluorescence emission spectra. Finally, photodynamic antimicrobial properties were assessed upon transfer on the colonies and following irradiation.