College of Chemistry & Molecular Sciences, Wuhan University , Wuhan 430072, People's Republic of China.
School of Materials Science and Engineering, South China University of Technology , Guangzhou 510641, People's Republic of China.
ACS Appl Mater Interfaces. 2016 Aug 3;8(30):19739-46. doi: 10.1021/acsami.6b05302. Epub 2016 Jul 25.
Most hydrogels involve synthetic polymers and organic cross-linkers that cannot simultaneously fulfill the mechanical and cell-compatibility requirements of biomedical applications. We prepared a new type of chitosan physical hydrogel with various degrees of deacetylation (DDs) via the heterogeneous deacetylation of nanoporous chitin hydrogels under mild conditions. The DD of the chitosan physical hydrogels ranged from 56 to 99%, and the hydrogels were transparent and mechanically strong because of the extra intra- and intermolecular hydrogen bonding interactions between the amino and hydroxyl groups on the nearby chitosan nanofibrils. The tensile strength and Young's modulus of the chitosan physical hydrogels were 3.6 and 7.9 MPa, respectively, for a DD of 56% and increased to 12.1 and 92.0 MPa for a DD of 99% in a swelling equilibrium state. In vitro studies demonstrated that mouse bone mesenchymal stem cells (mBMSCs) cultured on chitosan physical hydrogels had better adhesion and proliferation than those cultured on chitin hydrogels. In particular, the chitosan physical hydrogels promoted the differentiation of the mBMSCs into epidermal cells in vitro. These materials are promising candidates for applications such as stem cell research, cell therapy, and tissue engineering.
大多数水凝胶涉及合成聚合物和有机交联剂，它们不能同时满足生物医学应用的机械和细胞相容性要求。我们通过在温和条件下对纳米多孔壳聚糖水凝胶进行异相脱乙酰化，制备了具有不同脱乙酰度（DD）的新型壳聚糖物理水凝胶。壳聚糖物理水凝胶的 DD 范围为 56%至 99%，由于附近壳聚糖纳米纤维上的氨基和羟基之间的额外分子内和分子间氢键相互作用，水凝胶透明且机械强度高。壳聚糖物理水凝胶的拉伸强度和杨氏模量分别为 3.6 和 7.9 MPa，DD 为 56%，在溶胀平衡状态下增加到 12.1 和 92.0 MPa，DD 为 99%。体外研究表明，在壳聚糖物理水凝胶上培养的小鼠骨髓间充质干细胞（mBMSCs）比在壳聚糖水凝胶上培养的细胞具有更好的粘附和增殖能力。特别是，壳聚糖物理水凝胶促进 mBMSCs 体外向表皮细胞分化。这些材料有望应用于干细胞研究、细胞治疗和组织工程等领域。
