title: Enhanced electrokinetic properties and antimicrobial activities of biodegradable chitosan/organo-bentonite composites.
abstract: In this study, chitosan (CS), Na+-bentonite (Na+-BNT) and chitosan/organo-bentonite (CS/O-BNT) biodegradable composites having three different compositions were investigated. Electrokinetic measurements were examined in aqueous medium by taking the effects pH, electrolytes (NaCl and BaCl2), surfactants (CTAB and SDS), and temperature into account. It was noticed that the initial ζ-potential of Na+-BNT shifted from negative (ζ=-35mV) to positive region (ζ=+13mV) with increasing polycationic CS content in the composite structure as aimed. Divalent 2:1 electrolyte (BaCl2) caused to shift the ζ-potentials of all the dispersions to more positive regions. While the most negative effect on ζ-potential of the composites was reached with SDS, which reduced the value of ζ-potential to -39mV for CS(1)/O-BNT composite, the most positive effect was monitored with CTAB (ζ=+40mV) for CS(3)/O-BNT composite. Further, the composites were tested against various bacterial (Gram-positive and Gram-negative) and fungal microorganisms at various concentrations and results obtained were compared with the reference antibiotics and fungicide. According to inhibition zone values accomplished, antibacterial and antifungal activities of the CS/O-BNT composites are increased with increasing CS content as proportional with their positive ζ-potential values.
authors.affiliation: Department of Chemistry, Faculty of Arts and Sciences, Süleyman Demirel University, Isparta, Turkey. Electronic address: mehmetcabuk@sdu.edu.tr.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Cabuk
authors.affiliation: Faculty of Education, Muş Alparslan University, Muş, Turkey.
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Alan
authors.affiliation: Science Faculty, Chemistry Department, Gazi University, Ankara, Turkey.
authors.forename: H Ibrahim
authors.initials: HI
authors.lastname: Unal
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects*; D001546:Bentonite / Q000737:chemistry* / Q000494:pharmacology*; D048271:Chitosan / Q000737:chemistry* / Q000494:pharmacology*; D004563:Electrochemistry; D005658:Fungi / Q000187:drug effects*; D007700:Kinetics
chemical_list: D000890:Anti-Infective Agents; D001546:Bentonite; D048271:Chitosan
keywords: Antimicrobial activity; Chitosan; Fungicide; Organo-bentonite; SEM-EDS; Zeta potential