Using chitosan derivatives to determine bactericidal activity

(Nanowerk News) Researchers at National Nanotechnology Center, NANOTEC in Thailand, are doing research on the effects of the degree of quaternization, molecular weight and ratio of N-methylpyridinium and N,N,N-trimethyl ammonium moieties on bactericidal activity by introducing quaternization of N-(3-pyridylmethyl) chitosan derivatives.
"We found that the bactericidal activity was dependent on the chemical structure of quaternary ammonium moiety and the molecular weight, at constant DQ" said Dr. Warayuth Sajomsang, one of the research team members. "The result revealed that the N,N,N-trimethyl ammonium group showed higher bactericidal activity than the N-methylpyridinium group at similar DQ and molecular weight. Moreover, the bactericidal activity of M3-PyMeChC tended to decrease with decreasing molecular weight from 82 kDa to 8 kDa, at DQ of 80±2%".
"The bactericidal tests were performed in accordance with the National Committee for Clinical Laboratory Standards (NCCLS) to determine broth microdilution minimum inhibitory concentration (MIC) values" said Dr. Uracha Ruktanonchai, another member of the research team. "The microorganisms used in the inhibitory test were obtained from the Department of Medical Sciences (Ministry of Public Health, Thailand). The microorganisms used in this study were Staphylococcus aureus ATCC 6538 as a model for Grampositive bacteria and Escherichia coli ATCC 25922 as a model for Gram-negative bacteria".
The researchers reported their work in a paper published by Elsevier. The researchers at the NanoDelivery lab are currently working on research projects using nanoencapsulation and molecular complexation for controlled release and target delivery of bioactive compounds.