Synthesis of porphyrin-peptoid conjugates for antimicrobial and anticancer photodynamic therapy (PDT)

Abstract

Photodynamic therapy (PDT) has been developed mainly for cancer treatment, but recently emerged as a promising strategy to kill multi-drug resistant Gram-negative bacteria. To increase selectivity against bacteria and reduce hemolytic toxicity, conjugation of antimicrobial peptoids to photosensitizers (PSs) was performed. Hydrophobic photosensitizers in conjugation with peptoids became more hydrophilic, and cationic antimicrobial peptoids carry the photosensitizers into bacteria or cancer cells. Positively charged porphyrin conjugates appeared to enter Gram-negative bacteria resulting in considerable phototoxicity against E.coli. Neutral porphyrin conjugates exhibited selective photokilling effect against breast cancer HepG2 cell lines. Consequently, the results suggest that the PS-peptoid or PS-peptide conjugates provide a promising treatment strategy against both cancer and infectious disease.