Butler Michael F, Clark Allan H, Adams Sarah
Corporate Research, Unilever R&D Colworth, Sharnbrook, Bedfordhsire, MK44 1LQ United Kingdom.
Biomacromolecules. 2006 Nov;7(11):2961-70. doi: 10.1021/bm060133y.
Experimental and theoretical investigations of the swelling and mechanical properties of hydrogels formed from chitosan, bovine serum albumin (BSA), and chitosan/BSA mixtures cross-linked with genipin were performed. The properties of cross-linked chitosan hydrogels were explained in terms of its polyelectrolyte behavior, which led to a gradual increase in swelling ratio below the pK value, but whereby its swelling ability was eliminated by the presence of salt that screened the charges. Comparison of theoretical and experimental calculations of the swelling ratio, however, indicated that complications arising from wastage of cross-links, and formation of polymerized genipin cross-links must be considered before quantitative prediction can be achieved. Cross-linked BSA hydrogels swelled even in the presence of salt, and a marked increase in swelling was observed below pH = 3 that was explained as the result of an acid induced denaturation of the protein that led to unfolding of the molecule. Swollen BSA hydrogels were mechanically weak, however. Composite gels made from a cross-linked mixture of chitosan and BSA exhibited the swelling behavior of BSA combined with the mechanical properties of chitosan and were therefore considered most suitable for use in a gastric environment.
对由壳聚糖、牛血清白蛋白（BSA）以及与京尼平交联的壳聚糖/BSA混合物形成的水凝胶的溶胀和力学性能进行了实验和理论研究。交联壳聚糖水凝胶的性能根据其聚电解质行为进行了解释，这导致在pK值以下溶胀率逐渐增加，但盐的存在屏蔽了电荷，从而消除了其溶胀能力。然而，溶胀率的理论计算与实验计算的比较表明，在实现定量预测之前，必须考虑交联损耗和聚合京尼平交联的形成所带来的复杂性。交联的BSA水凝胶即使在有盐的情况下也会溶胀，并且在pH = 3以下观察到溶胀显著增加，这被解释为蛋白质酸诱导变性导致分子展开的结果。然而，溶胀的BSA水凝胶力学性能较弱。由壳聚糖和BSA的交联混合物制成的复合凝胶表现出BSA的溶胀行为以及壳聚糖的力学性能，因此被认为最适合在胃环境中使用。
