Balance of disinfection and cytotoxicity of hydroxypropyltrimethyl ammonium chloride chitosan with polyhexamethylene biguanide at low concentrations

ABSTRACT

Any microorganisms killing molecules have some cytotoxicity more or less. The effective way of reducing cytotoxicity mainly included two approaches: One was reducing the concentration of antiseptic, while this would lead to the decreased antimicrobial efficiency; the other way was choosing suitable antiseptics and then combining of them, which can balance the disinfection and cytotoxicity. In this paper, hydroxypropyltrimethyl ammonium chloride chitosan (HACC), a cationic natural macromolecular, as the first antiseptic, incorporated with polyhexamethylene biguanide (PHMB), a smaller molecular weight cationic antiseptic polymer, as the second antiseptic, their disinfection effect and cell cytotoxicity in borate buffer solution were investigated at fairly low contents. When HACC/PHMB weight ratios were 100/1 and 150/1, the disinfection solutions produced >1-log reductions against C. albicans and >3-log reductions against S. aureus and P. aeruginosa. HACC/PHMB disinfection solution at weight ratio of 150/1 even showed a highest antimicrobial efficiency and the cell proliferation rates were approximately 100% in MTT assays. Meanwhile, the research of micromorphology and fluorescence spectra indicated that bigger aggregation state of HACC-PHMB were helpful to improve antimicrobial ability. These results showed that the HACC-PHMB combination might be a promising candidate for novel antimicrobial group for biomedical applications.

KEYWORDS:

• hydroxypropyltrimethyl ammonium chloride chitosan
• polyhexamethylene biguanide
• antimicrobial activity
• nontoxicity
• optical microscopy
• fluorescence spectra

Funding

This work was supported by the National Nature Science Foundations of China (81571812), a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (1107047002) and Hydron contact lens co., LTD (8507040152).