title: Preparation and characterization of dispersible chitosan particles with borate crosslinking and their antimicrobial and antifungal activity.
abstract: We synthesized new dispersive chitosan particles at circumneutral pH. Particles composed of a chitosan-borate complex were synthesized by a method consisting of two simple steps: mixture and dialysis. As this method does not employ reagents such as organic solvents or surface-active agents and does not require heat treatment, it has a minimal negative impact on the environment. Crosslinking of the reaction of glucose and boric acid at ordinary temperature and pressure led to the formation of composite particles. Stereoscopic microscopy and investigation of the particle size distribution by dynamic light scattering (DLS) revealed that particles ranging in size from submicrons to several microns with high dispersibility in water were obtained. Even after heat treatment at 80°C for 12h, the particles maintained their composite formation, indicating that they have high thermal stability. Chitosan powders demonstrated inadequate antimicrobial properties at circumneutral pH, but the particles of the chitosan-borate complex had antimicrobial properties against the gram-negative bacterium, Escherichia coli, and the gram-positive bacterium, Staphylococcus aureus, as well as the fungi Aspergillus niger and Fusarium solani. These results indicated that the particles of the chitosan-borate complex had a broad antimicrobial spectrum at circumneutral pH.
authors.affiliation: Department of Applied Chemistry & Biochemistry, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Saita
authors.forename: Shoji
authors.initials: S
authors.lastname: Nagaoka
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Shirosaki
authors.forename: Maki
authors.initials: M
authors.lastname: Horikawa
authors.forename: Shigeki
authors.initials: S
authors.lastname: Matsuda
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Ihara
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000935:Antifungal Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D001234:Aspergillus niger / Q000187:drug effects; D001881:Borates / Q000737:chemistry*; D002240:Carbohydrate Sequence; D048271:Chitosan / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D004926:Escherichia coli / Q000187:drug effects; D005670:Fusarium / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010316:Particle Size; D011312:Pressure; D013211:Staphylococcus aureus / Q000187:drug effects; D013329:Structure-Activity Relationship; D013499:Surface Properties; D013696:Temperature
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D001881:Borates; D003432:Cross-Linking Reagents; D048271:Chitosan