Patent ID: 8193325

Claim:
A method for producing nano-miniaturized chitosan of colloidal gel structure, comprising: (a)(i) reducing the molecular weight of chitosan by dissolving chitosan of a high molecular weight in a diluted acid solution under controlled specific temperature for different reacting times so as to obtain chitosan having a molecular weight between 10 and 50 kD, and/or (ii) modifying (A) chitosan of high molecular weight or (B) chitosan of molecular weight between 10 and 50 kD of step (a)(i) by dissolving the chitosan in a well-mixed solution of water and methanol, introducing iodomethane (CH 3 I) and sodium chloride (NaCl) to the solution, separating the chitosan by acetone precipitation, drying the chitosan using decompressed drying, and dissolving the chitosan in an aqueous solution of de-ionized water, so as to obtain chitosan wherein the amine radical functional group of the chitosan is modified into a quaternary ammonium salt functional group; and (b) nano-miniaturizing the chitosan of step (a) by a sol-gel method comprising adding an adequate quantity of alkali to the chitosan of step (a), and hydrolyzing, condensing, and polymerizing the chitosan, so as to produce a nano-miniaturized chitosan of colloidal gel structure, wherein the particle diameter for said nano-miniaturized chitosan of colloidal gel structure is approximately between 40 and 150 nm.