title: Preparation, characterization, and antimicrobial activity of quaternized chitosan/organic montmorillonite nanocomposites.
abstract: Quaternized chitosan/layered silicate nanocomposite was prepared by simple solution-mixing in aqueous media. Montmorillonite (MMT) modified with cetyltrimethyl ammonium bromide was used as an organically modified layered silicate. XRD and TEM analyses respectively confirmed that silicate layers of MMT were intercalated and nicely distributed in quaternized chitosan matrix in despite of the high content of MMT (25-50 wt %). The interactions between the quaternized chitosan macromolecules and MMT in aqueous media were analyzed using FTIR, XRD, and zeta-potential measurements. Antimicrobial studies showed that the nanocomposites could strongly inhibit the growth of a wide variety of microorganisms, including Gram-positive bacteria, Gram-negative bacteria, and fungi; more importantly, they exhibited good antimicrobial capacity in whichever medium, in weak acid, water, or weak base. As the amount of MMT increased, the nanocomposites had better inhibitory effect on microorganisms, especially Gram-positive bacteria. The lowest minimum inhibition concentration (MIC) value of the nanocomposites against Staphylococcus aureus and Bacillus subtilis were less than 0.00313% (w/v) under all the conditions. The adsorption action of MMT on bacteria was simply discussed via SEM images. The results revealed that the strong antimicrobial of the nanocomposites may be attributed to the fine dispersion and the interaction between quaternized chitosan and MMT.
authors.affiliation: Department of Environmental Science, College of Resource and Environmental Science, Wuhan University, Wuhan 430079, China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Wang
authors.forename: Yumin
authors.initials: Y
authors.lastname: Du
authors.forename: Jianhong
authors.initials: J
authors.lastname: Yang
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Tang
authors.forename: Jiwen
authors.initials: J
authors.lastname: Luo
mesh_terms: D000818:Animals; D001419:Bacteria / Q000187:drug effects; D001422:Bacterial Adhesion / Q000187:drug effects; D001546:Bentonite / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D048271:Chitosan / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D002593:Cetrimonium Compounds; D001546:Bentonite; D048271:Chitosan; D000077286:Cetrimonium