Antibacterial performance of cationic quaternary phosphonium-modified chitosan polymer in water

Microbial contamination in water has emerged as a critical concern and thus developing biocide materials for controlling microbial contamination is crucial. Removing all pathogenic bacteria in water is difficult when using traditional water treatment technologies. Moreover, these bacteria can easily reproduce during pipeline distribution. In this work, a facile and effective chitosan derivative biocide denoted as PCC was developed by grafting with quaternary phosphonium salt (QPS). PCC became positively charged with a wide range of pH and demonstrated antibacterial activity up to 95% and 100% against Escherichia coli and Staphylococcus aureus as model pathogens, respectively. The grafting of QPS may disrupt the cell membrane and lead to bacterial inactivation, as demonstrated by the scanning electron microscopy image and the concentration of intracellular substance leakage. MTT assay results indicate that PCC achieved good biocompatibility with negligible in vitro cytotoxicity. These findings introduce a promising approach for bacterial decontamination due to its low cytotoxicity and high biocidal activity.