Polymyxin B/chlorine e6 conjugated hyaluronate dot particles for antimicrobial photodynamic therapy

In this study, we report ultrafine-sized antibiotic dot particles targeting gram-negative bacteria. The water-soluble ultrafine-sized hyaluronate dot (dHA) was conjugated with polymyxin B (PMB, as a target material for lipopolysaccharide on a gram-negative bacteria) and chlorine e6 (Ce6, as a model photosensitizer), and it was denoted as dHA-(PMB/Ce6). These dot particles interacted with lipopolysaccharide (LPS) on gram-negative bacteria, which enabled PMB-mediated docking to the outer membrane of gram-negative cells. In the antimicrobial experiments using Escherichia coli cells, the phototoxic singlet oxygen generated from the dHA-(PMB/Ce6) under light irradiation inhibited E. coli cell growth. This demonstrated that dHA-(PMB/Ce6) can provide light-activated selective phototoxicity against gram-negative bacteria. We expect that the dot particle system can be used as an efficient method for improved antimicrobial treatment.