title: Antimicrobial activities and cellular responses to natural silicate clays and derivatives modified by cationic alkylamine salts.
abstract: Nanometer-scale silicate platelet (NSP) materials were previously developed by increasing the interlayer space and exfoliation of layered silicate clays such as montmorillonite and synthetic fluorinated mica by the process of polyamine exfoliation. In this study, the antibacterial activity and cytotoxicity of these nanometer-scale silicate clays were evaluated. The derivatives of NSP (NSP-S) which were modified by C18-fatty amine salts via ionic exchange association exhibited the highest antibacterial activity in the aqueous state among all clays. The high antibacterial activity, however, was accompanied by elevated cytotoxicity. The variations of cell surface markers (CD29 and CD44) and type I collagen expression of fibroblasts treated with the clays were measured to clarify the mechanism of the silicate-induced cytotoxicity. The signal transduction pathway involved the downregulation of extracellular-signal-regulated kinase (ERK), which appeared to participate in silicate-induced cytotoxicity. This study helped to understand the antibacterial potential of NSP and the interaction of natural and modified clays with cellular activities.
authors.affiliation: Institute of Polymer Science and Engineering, National Taiwan University, Taipei 10617 Taiwan, Republic of China. shhsu@ntu.edu.tw
authors.forename: Shan-Hui
authors.initials: SH
authors.lastname: Hsu
authors.forename: Hsiang-Jung
authors.initials: HJ
authors.lastname: Tseng
authors.forename: Huey-Shan
authors.initials: HS
authors.lastname: Hung
authors.forename: Ming-Chien
authors.initials: MC
authors.lastname: Wang
authors.forename: Chiung-Hui
authors.initials: CH
authors.lastname: Hung
authors.forename: Pei-Ru
authors.initials: PR
authors.lastname: Li
authors.forename: Jiang-Jen
authors.initials: JJ
authors.lastname: Lin
mesh_terms: D000538:Aluminum Silicates / Q000494:pharmacology*; D000588:Amines / Q000737:chemistry*; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001546:Bentonite / Q000494:pharmacology; D002412:Cations; D002417:Cattle; D016923:Cell Death / Q000187:drug effects; D000077215:Clay; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D015169:Colony Count, Microbial; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D019012:Integrin beta1 / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D010766:Phosphorylation / Q000187:drug effects; D012492:Salts / Q000737:chemistry*; D017640:Silicates / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure
chemical_list: D000538:Aluminum Silicates; D000588:Amines; D000890:Anti-Infective Agents; D002412:Cations; D024042:Collagen Type I; D018960:Hyaluronan Receptors; D019012:Integrin beta1; D012492:Salts; D017640:Silicates; D001546:Bentonite; D048049:Extracellular Signal-Regulated MAP Kinases; D000077215:Clay