抄録
Chitosan sub-micron particles were prepared by ion exchange phase separation method as follows: 1) chitosan was dissolved in lactic acid aqueous solution: 2) the obtained chitosan solution was dropped in polyvalent anion salt aqueous solution, i.e. dianion salt, trianion salt solution: 3) desalinating and deacidifying from aqueous dispersion of chitosan submicron particles was carried out by dialyzing tube method. The aqueous dispersion of chitosan particles, which was prepared using aqueous solution of polyvalent anion salt appeared cloudy. This phenomenon was attributed to cross-linking by ion interaction between sulfate anion and amino groups in glucosamine unit. The chitosan aggregates were confirmed to promote with increase of amount of Na2SO4 by dynamic light scattering method. This indicates that agglutination sites among chitosan particles increased as the number of the sulfate anion coupled with amino group increased. As results, the chitosan particles of sub-micron size were prepared by adding 1.0 equivalent of Na2SO4 against an amount of amino groups to dispersion medium. In addition, we investigated the antibacterial activity test for Escherichia coli of obtained chitosan particles. The chitosan sub-micron particles showed significantly antibacterial activity at concentration of 5.0 mg/ml, in spite of incubation in neutrality condition (pH 7.1-7.6).
