title: Structural effect of quaternary ammonium chitin derivatives on their bactericidal activity and specificity.
abstract: The effect of the quaternary ammonium chitin structure on the bactericidal activity and specificity against Escherichia coli and Staphylococcus aureus was investigated. Quaternary ammonium chitins were synthesized by the separate acylation of chitin (CT) with carboxymethyl trimethylammonium chloride (CMA), 3-carboxypropyl trimethylammonium chloride (CPA) and N-dodecyl-N,N-(dimethylammonio)butyrate (DDMAB). The successful acylation was confirmed by newly formed ester linkage. All three derivatives had a higher surface charge than chitin due to the additional positively charged quaternary ammonium groups. The N-short alkyl substituent (methyl) of CTCMA and CTCPA increased the hydrophilicity whilst the N-long alkyl substituent (dodecyl) of CTDDMAB increased the hydrophobicity compared to chitin. Chitin did not exhibit any bactericidal activity, while CTCMA and CTCPA completely killed E. coli and S. aureus in 30 and 60min, respectively, and CTDDMAB completely killed S. aureus in 10min but did not kill E. coli after a 2-h exposure. Therefore, the N-short alkyl substituent was more effective for killing E. coli and the N-long alkyl substituent conferred specific bactericidal activity against S. aureus.
authors.affiliation: Department of Materials Science, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand.
authors.forename: Tirut
authors.initials: T
authors.lastname: Morkaew
authors.affiliation: Department of Microbiology, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand.
authors.forename: Onruthai
authors.initials: O
authors.lastname: Pinyakong
authors.affiliation: Department of Materials Science, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand. Electronic address: Wanpen.Ta@chula.ac.th.
authors.forename: Wanpen
authors.initials: W
authors.lastname: Tachaboonyakiat
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D002686:Chitin / Q000737:chemistry*; D004926:Escherichia coli / Q000187:drug effects; D057927:Hydrophobic and Hydrophilic Interactions; D008826:Microbial Sensitivity Tests; D000644:Quaternary Ammonium Compounds / Q000737:chemistry* / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D000644:Quaternary Ammonium Compounds; D002686:Chitin
keywords: Antibacterial; Chitin; Quaternary ammonium; Specificity