Novel Branched Polyamine-Modified Chlorin with a Photoinduced Antimicrobial Activity

Multiple drug resistance is one of the major threats to global health. One of the approaches to solving this problem is antimicrobial photodynamic therapy, however, currently used photosensitizers are not sufficiently effective against pathogens. Polycationic molecular constructs enhance the binding and penetration of photosensitizers into poorly permeable gram-negative bacteria. Such conjugates can be obtained by introducing polyethyleneimines into a photosensitizer molecule. In this study, we synthesized a branched tetraamine and introduced it into the pyrrole ring A of the natural chlorin molecule and assessed in vitro the photoinduced toxicity of the new photosensitizer against Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, and Escherichia coli bacteria. Compared to its structural precursor, the obtained chlorin with a branched polyamine residue demonstrated an increased bactericidal effect when irradiated with light.