Chitosan originating from crustaceans with 90% deacetylation
and viscosity of 15 cP was obtained from Ocean University
of China. It was dissolved at 2% (w/v) in 1% HCl by stirring
overnight at room temperature, and the original solution
was then diluted to a series of 0.01, 0.05, 0.1, 0.5 and 1%,
and the pH value of each solution was adjusted to 5.4 with
NaOH.