One-Pot Synthesis of a Cyclic Antimicrobial Peptide-Conjugated Phthalocyanine for Synergistic Chemo-Photodynamic Killing of Multidrug-Resistant Bacteria

Jacky C.H. Chu, Miu Ling Chin, Clarence T.T. Wong (Corresponding Author), Mamie Hui, Pui Chi Lo, Dennis K.P. Ng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

9 Citations (Scopus)


Multidrug-resistant (MDR) bacteria pose a serious threat to public health globally. Among the various antimicrobial modalities that have recently emerged, photodynamic therapy has received considerable attention because of its various potential advantages, including the unlikelihood of inducing drug resistance. A facile synthetic approach is reported to prepare a phthalocyanine-based photosensitizer conjugated with a cyclic bactenecin peptide. This one-pot procedure that involves site-selective alkylation of the two cysteine residues of a linear bactenecin peptide followed by Diels–Alder reaction leads to the formation of the conjugate labeled as cBac-Pc in 27% isolated yield. As shown by confocal fluorescence microscopy, this conjugate shows selective affinity toward bacterial over mammalian cells. It can also induce synergistic cytotoxic effects due to the cyclic peptide and phthalocyanine against a spectrum of Gram-positive and Gram-negative bacterial strains, including two ATCC-type strains and two clinical isolates of MDR bacterial strains. It is believed that the inhibition mechanism is based on the physical destruction of the cell membrane due to the cyclic peptide followed by photodynamic action induced by the phthalocyanine unit.

Original languageEnglish
Article number2000204
JournalAdvanced Therapeutics
Issue number3
Publication statusPublished - Mar 2021
Externally publishedYes


  • antimicrobials
  • cyclization
  • peptides
  • photodynamic therapy
  • phthalocyanines

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Biochemistry, medical
  • Pharmacology (medical)
  • Genetics(clinical)
  • Pharmaceutical Science
  • Pharmacology

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