title: Quaternized chitosans bind onto preexisting biofilms and eradicate pre-attached microorganisms.
abstract: Quaternized chitosans, N,N,N-trimethylchitosans (TMC) with different degree of quaternization were synthesized by reacting methyl iodide with chitosan. The reaction was confirmed by FT-IR and1H-NMR characterization. Antimicrobial assay showed that the prepared TMC had potent biocidal effects against planktonic Gram-positive bacteriaStaphylococcus epidermidis, Gram-negative bacteriaEscherichia coli, and yeastCandida albicans. Bacterial and fungal biofilms were formed on poly(methyl methacrylate) (PMMA) films and then treated with TMC aqueous solutions. Zeta potential measurement suggested that TMC bonded onto the preexisting biofilms. Biofilm-binding kinetics was evaluated in UV studies using phenyl group-labeled TMC as model compounds, which revealed that quaternized chitosans bonded onto the preexisting biofilms rapidly. Colony-forming unit (CFU) determination and SEM, confocal laser scanning microscopy (CLSM) and fluorescence microscopy studies demonstrated that the bonded TMC had powerful biocidal activities to eradicate the pre-attached bacterial and fungal cells in the preexisting biofilms. The biocompatibility of the TMC samples with rat skin fibroblast cells was evaluated in the MTT assay.
authors.affiliation: Department of Chemistry, University of Massachusetts, Lowell, MA 01854, USA, ; Tel: +1 978 934 3637, yuyu_sun@uml.edu.
authors.forename: Fuguang
authors.initials: F
authors.lastname: Jiang
authors.affiliation: Biomedical Engineering Program, University of South Dakota, Sioux Falls, SD 57107, USA, ; Tel:+1 605 367 7775, ying.deng@usd.edu.
authors.forename: Ying
authors.initials: Y
authors.lastname: Deng
authors.affiliation: Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, and Geriatric Research, Education and Clinical Center, Audie L. Murphy Division South Texas Veterans Health Care System, San Antonio, TX 78229 USA, ; Tel: +1 210 617 5197, yeh@uthscsa.edu.
authors.forename: Chih-Ko
authors.initials: CK
authors.lastname: Yeh
authors.affiliation: Department of Chemistry, University of Massachusetts, Lowell, MA 01854, USA, ; Tel: +1 978 934 3637, yuyu_sun@uml.edu.
authors.forename: Yuyu
authors.initials: Y
authors.lastname: Sun
keywords: Biocides; Biocompatible; Biofilm-binding; Quarternized chitosan