LAUSR

The syntheses and characterisation of novel octacationic and hexadecacationic Pcs is reported. With the aim of enhancing their singlet oxygen generation efficiencies and hence antimicrobial activities, these Pcs (including their neutral counterpart) are conjugated to Ag nanoparticles. The obtained results show that the conjugate composed of the neutral Pc has a higher loading of Pcs as well as a greater singlet oxygen quantum yield enhancement in DMSO. The antimicrobial efficiencies of the Pcs and their conjugates were evaluated and compared on S. aureus, E. coli and C. albicans. The cationic Pcs possess better activity than the neutral Pc against all the microorganisms with the hexadecacationic Pc being the best. This work therefore demonstrates that increase in the number of cationic charges on the reported Pcs results in enhanced antimicrobial activities, which is maintained even when conjugated to Ag nanoparticles. The high activity and lack of selectivity of the cationic Pcs when conjugated to Ag NPs against different microorganisms makes them good candidates for real life antimicrobial treatments.