Over the decades, guanidine-based oligomer groups have been one of the most widely used antimicrobial agents. Reportedly, these cationic oligomers cause serious damage to microorganisms but have low toxicity to humans. However, public concerns regarding the guanidine group have rapidly grown after the fatal misuse of these oligomers as humidifier disinfectants, which resulted in thousands of fatalities in South Korea. Herein, we investigated liposome leakage and cellular permeability changes caused by polyhexamethylene guanidine (PHMG) and polyhexamethylene biguanide (PHMB), both representative guanidine-based oligomers. The leakage of zwitterionic liposomes, induced by cationic oligomers, was more extensive than that of negative liposomes, indicating that oligomer adsorption onto lipid head groups via electrostatic interaction cannot fully explain the induced lipid membrane damage. Furthermore, lipid packing parameters, including intrinsic curvature, cholesterol content, and lipid phases, affected liposome leakage, particularly for PHMG. Cellular permeability tests were performed using an A549 cell monolayer model and a respiratory 3D tissue model, revealing that PHMG and PHMB damaged cell membranes and reduced cell barrier function. Furthermore, liposome leakage induced by PHMG and PHMB was higher in human lung surfactant-mimicking liposomes than that observed in Escherichia coli-mimicking liposomes. These results indicated that human cells are susceptible to guanidine-based oligomers. Considering that the interaction of oligomers and cell membranes is a major mechanism of toxicity initiation, this study provides crucial insights into the action of these disinfectants on mammalian cells. This journal is
Bibliographical noteFunding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (NRF-2019R1I1A1A01059970) and by the Korea Environment Industry & Technology Institute (KEITI) through “Technology Development Project for Safety Management of Household Chemical Products” funded by the Korea Ministry of Environment (MOE) (No. 2020002970001 and 1485017105).
© The Royal Society of Chemistry.
ASJC Scopus subject areas
- General Chemistry
- General Chemical Engineering