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Updated: Aug 6, 2026

Visualization of Bacterial Resistance using Fluorescent Antibiotic Probes
08:23

Visualization of Bacterial Resistance using Fluorescent Antibiotic Probes

Published on: March 2, 2020

Quaternary Ammonium-Functionalized Membrane-Anchored Photosensitizer against Multidrug-Resistant Bacterial Infections

Yan Zeng1, Hui Tang2, Xinyu Wu2

  • 1Department of Food Quality and Safety/National R&D Center for Chinese Herbal Medicine Processing, College of Engineering, China Pharmaceutical University, Nanjing211198, China.

Molecular Pharmaceutics
|July 22, 2026
PubMed

Insights

A new quaternary ammonium photosensitizer, PK4, effectively combats drug-resistant bacteria like MRSA using light-activated ROS. This promising antimicrobial photodynamic therapy accelerates wound healing with minimal toxicity.

Area of Science:

  • Photodynamic Therapy
  • Antimicrobial Resistance
  • Materials Science

Background:

  • Bacterial resistance to antibiotics is a growing global health threat.
  • Antimicrobial photodynamic therapy (aPDT) offers an alternative by using light-activated reactive oxygen species (ROS) to kill bacteria.
  • Conventional photosensitizers face challenges like aggregation, poor selectivity, and toxicity.

Purpose of the Study:

  • To develop a novel photosensitizer for aPDT targeting drug-resistant bacteria.
  • To evaluate the efficacy and safety of the quaternary ammonium photosensitizer PK4.

Main Methods:

  • Synthesis and characterization of the quaternary ammonium photosensitizer PK4.
  • Evaluation of ROS production and phototoxicity under white light irradiation.
  • Assessment of PK4-mediated aPDT in a methicillin-resistant Staphylococcus aureus (MRSA) infected wound model.

Main Results:

  • PK4 demonstrated high photostability and produced abundant ROS upon light activation.
  • PK4 exhibited minimal dark toxicity and preferential accumulation on bacterial membranes.
  • PK4-mediated aPDT significantly reduced inflammation, accelerated wound healing, and increased collagen deposition in the MRSA wound model.

Conclusions:

  • PK4 is a promising photosensitizer for aPDT against drug-resistant bacteria.
  • PK4-mediated therapy offers a safe and effective strategy for treating MRSA-infected wounds.
  • This approach addresses limitations of conventional photosensitizers and antibiotic resistance.
Keywords:
bacterial infectionphotodynamic antibacterialphotosensitizersquaternary ammonium salts

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