"Entrapment of anionic porphyrins in nanofabrics modified by cyclodextrin: spectroscopy, morphological investigation and antimicrobial photosensing activity"

The increasing global occurrence of infectious diseases caused by multiantibiotic-resistant microbial pathogens represents nowadays a major challenge. Recent results suggest that photodynamic antimicrobial chemiotherapy (PACT) could represent a useful tool for correctly addressing this problem at least in the case of restricted infections. In this scenario cationic porphryins may strengthen their photobactericidal effect by incorporation into amphiphilic cationic cyclodextrins as a consequence of the carrier ability to promote an efficient crossing of the bacterial wall by the very tightly organized three-dimensional architecture.1 The grafting of native or modified cyclodextrins (CD) onto cotton, wool, and polyester fabrics, by using polycarboxylic acids (PCA) as crosslinking agents is of increasing interest. This finishing reaction offered new properties to the textiles, as they present enhanced properties of sorption and controlled delivery of many active molecule through their inclusion into the grafted CD cavities.3In this contribute we report the complexation of anionic porphyrins in a hydroxyl-propyl CD polymer fixed onto nonwoven supports made of polyethylproylene fibers by using PCA as crosslinker. 5,10,15,20-tetrakis(4- sulfonatophenyl)-21H,23H-porphine (TPPS) and meso-tetrakis(4-carboxyphenyl)porphyrin (TPPC) were respectively transferred on the tissue from aqueous solutions and by a dispersion containing a supramolecular adduct of TPPC with O-(2-aminopropyl)-O-(2-methoxyethyl)poly(propylene glycol) (Jeffamine M-600). The solid substrates were investigated by complementary techniques including reflectance UV spectroscopy, state-stationary and time resolved fluorescence emission, Field-Emission Scanning Electron Microscopy (FE-SEM). The antibacterial efficacy of functionalized patch was investigated by a comparison of the number of viable cells in the Staphylococcus aureus suspension incubated with fabrics entrapping TPPS which was previously irradiated, compared to a sample not irradiated. A remarkable reduction in viability compared to the non irradiated sample was shown. Fluorescence microscopy, extinction and emission spectra on the cells, evidence that TPPS is released from fabrics and can bind to the bacterial wall, accomplishing the photocytotoxic action.