Heterogeneous Fenton’s-like catalyst potentiation of hydrogen peroxide disinfection: an investigation into mechanisms of action

Abstract

Aims This study aimed to establish the mechanisms of action (MOA) of a novel surface functionalised polyacrylonitrile (PAN) catalyst, which was previously shown to have potent antimicrobial activity in conjunction with hydrogen peroxide (H2O2). Methods and results Bactericidal activity was determined using a disinfectant suspension test. The MOA was investigated by measuring loss of 260 nm absorbing material, membrane potential and permeability assays, analysis of intra- and extracellular ATP and pH, and tolerance to sodium chloride and bile salts. The catalyst lowered sub-lethal concentrations of H2O2 from 0.2% to 0.09%. H2O2 ± 3 g PAN catalyst significantly (P ≤ 0.05) reduced sodium chloride and bile salt tolerance, suggesting the occurance of sublethal cell membrane damage. The catalyst significantly increased (P ≤ 0.05) N-Phenyl-l-napthylamine uptake (1.51-fold) and leakage of nucleic acids, demonstrating increased membrane permeability. A significant (P ≤ 0.05) loss of membrane potential (0.015 a.u.), coupled with pertubation of intracellular pH homeostasis and depletion of intracellular ATP, suggests potentiation of H2O2-mediated cell membrane damage. Conclusions This is the first study to investigate the catalyst's antimicrobial mechanism of action, with the cytoplasmic membrane being a target for cellular injury.