氧化海藻酸钠(OSA)作为一种合适的材料被广泛应用于再生医学中。3D打印/复合脚手架,和组织工程以其优异的理化性质和生物降解性。然而,很少有文献系统地研究了所得OSA的结构和性质以及海藻酸盐的氧化度（OD）对其生物降解性和凝胶化能力的影响。在这里，我们使用NaIO4作为氧化剂氧化藻酸盐糖醛酸单体上C-2和C-3位的相邻羟基，以获得具有各种OD的OSA。利用傅里叶变换红外光谱(FT-IR)对OSA的结构和理化性质进行了研究,1H核磁共振(1HNMR),X射线光电子能谱(XPS),X射线衍射(XRD)和热重分析(TGA)。同时,使用凝胶渗透色谱（GPC）和流变仪来确定OSA的水凝胶形成能力和生物降解性能。结果表明,海藻酸糖醛酸单元的两个相邻羟基被成功氧化形成醛基;随着NaIO4用量的增加,OSA的OD逐渐增加，分子量下降，凝胶化能力持续减弱,降解性能明显上升。结果表明，通过调节NaIO4和海藻酸钠（SA）的摩尔比，可以制备具有多种OD的OSA，大大拓宽了OSA基水凝胶在组织工程中的应用,控制药物释放，3D打印,和生物医学领域。
Oxidized sodium alginate (OSA) is selected as an appropriate material to be extensively applied in regenerative medicine, 3D-printed/composite scaffolds, and tissue engineering for its excellent physicochemical properties and biodegradability. However, few literatures have systematically investigated the structure and properties of the resultant OSA and the effect of the oxidation degree (OD) of alginate on its biodegradability and gelation ability. Herein, we used NaIO4 as the oxidant to oxidize adjacent hydroxyl groups at the C-2 and C-3 positions on alginate uronic acid monomer to obtain OSA with various ODs. The structure and physicochemical properties of OSA were evaluated by Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (1H NMR), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), and thermogravimetric analysis (TGA). At the same time, gel permeation chromatography (GPC) and a rheometer were used to determine the hydrogel-forming ability and biodegradation performance of OSA. The results showed that the two adjacent hydroxyl groups of alginate uronic acid units were successfully oxidized to form the aldehyde groups; as the amount of NaIO4 increased, the OD of OSA gradually increased, the molecular weight decreased, the gelation ability continued to weaken, and degradation performance obviously rose. It is shown that OSA with various ODs could be prepared by regulating the molar ratio of NaIO4 and sodium alginate (SA), which could greatly broaden the application of OSA-based hydrogel in tissue engineering, controlled drug release, 3D printing, and the biomedical field.
