Study of Chitin and Chitosan for Bio-medical Materials Application

我们已经发现甲壳素溶解在氯化钙二水合物饱和甲醇中形成澄清溶液。在简要的研究中，甲壳素的溶解行为取决于溶液中钙、甲醇和水的含量。由于甲壳素在高含水量介质中溶解度急剧下降，在甲壳素溶液中加入水可形成甲壳素水凝胶。所获得的材料是含有超过95%的水的高度溶胀的水凝胶。需要透析以从水凝胶中除去过量的钙。以相同的方式，在甲壳质溶液中加入甲醇也得到凝胶状材料。然而，需要两倍量的甲醇才能从甲壳质溶液中沉淀出来。此外，需要长期透析以从凝胶材料中去除钙。这些结果表明，不同的溶解条件是不同的。比较了甲壳素水凝胶和粉末的酶消化率。甲壳素水凝胶比粉末用几丁质酶和溶菌酶消化快约10倍。结果表明，甲壳素水凝胶具有良好的生物相容性和生物消化特性，适合于生物医用。从甲壳质水凝胶中除去水再次再生甲壳质。在此基础上，通过使用常规过滤装置除去水，得到甲壳素片。一旦从甲壳质水凝胶中除去水，加入水不再得到水凝胶。这一现象可能是通过甲壳素分子间氢键网络的再生实现的。这张纸非常有趣，因为这是一张由100%甲壳素组成的纸，没有任何胶水。染料吸附实验表明，该载体对阴离子染料有较高的选择性，提示其作为药物载体的可能性。

We have found that chitin dissolves in calcium chloride dihydrate saturated methanol to form a clear solution. In the briefly study, solubility behavior of chitin depend on the calcium, methanol and water content of the solution. Since the solubility of chitin decreased drastically in the medium of high water content, the chitin hydro gel appeared by the addition of water in the chitin solution. Obtained material was a highly swelled hydro gel containing more than 95 % of water. Dialysis was necessary to remove excess calcium from the hydro gel. In the same manner, addition of methanol in the chitin solution also gave gel like material. However, two fold amount of methanol was required to precipitate out from the chitin solution. In addition, long term dialysis was necessary to remove calcium from the gel material. These results suggest that the solubility condition is different from each other.Properties of the chitin hydro gel were examined by several manners. Enzyme digestion rate of chitin hydro gel was compared with that of powder. Chitin hydro gel digested about ten times faster than powder using chitinase and lysozime. The results strongly suggests that chitin hydro gel has excellent biocompatible and biodigestive feature and is appropriate for bio medical usage. Removal of water from the chitin hydro gel regenerated chitin again. Based on the result, the removal of water by the use of conventional filtration apparatus gave chitin sheet. Once the water was removed from the chitin hydro gel, addition of water did not gave hydro gel again. The phenomenon may be carried out by the regeneration of hydrogen bond network between chitin molecules. The sheet is very interesting because this is a sheet made up of 100 % of chitin without of any glue. Dye adsorption examination afforded high preference for anionic dye, which suggest the possibility for the carrier of drug delivery system.