Photosensitive dendrimers as a good alternative to antimicrobial photodynamic therapy of Gram-negative bacteria

Abstract

This article describes the antimicrobial activity and cytotoxicity of two photoactive PAMAM dendrimers modified with 1,8-naphthalimides. The compounds investigated absorb in the visible spectral region and emit yellow-green fluorescence. It has been found that antimicrobial activity against Gram-negative bacteria P. aeruginosa has enhanced more than twice upon daylight irradiation indicating the applicability of the dendrimers in the design of substances for photodynamic antibacterial therapy. The antibacterial activity of the dendrimers is saved after their deposition onto cotton fabric. The bacterial growth inhibition is due to the generation of singlet oxygen by the photoactive dendrimers. Its production has been investigated by photo-oxidation of KI to I3− under light irradiation. The cytotoxicity of the studied dendrimers has been investigated on HEp-2 cells. Low cytotoxicity has been observed after deposition of dendrimers on the cotton fabrics.