氧化海藻酸钠是一种易于修饰的多糖,由于其侧基醛基可以与胺形成动态共价键,酰基肼,等。,提供具有刺激响应特性的氧化海藻酸钠基水凝胶。然而,由于刚度和,特别是,海藻酸钠二醛在低pH下的疏水性,氧化海藻酸钠基水凝胶的机械性能和pH刺激响应性仍然受到严格限制。在这里,我们报告了一个新的策略来制造一种注射剂,双重响应,以及基于氧化海藻酸钠和酰肼改性的聚乙二醇(PEG)的自修复水凝胶。酰肼修饰的PEG,称为PEG-DTP,作为大分子交联剂。我们发现PEG-DTP的存在有效地降低了氧化海藻酸钠在低pH下的疏水性,甚至可以实现pH诱导的可逆溶胶-凝胶转变。同时,PEG-DTP中的二硫键通过氧化还原刺激赋予水凝胶以其他可逆的溶胶-凝胶转变。特别是,由于PEG-DTP链的柔软性,机械性能也显著提高。我们的结果表明我们可以很容易地整合多刺激反应性,可注射性,仅通过将氧化的海藻酸钠溶液与PEG-DTP溶液以一定比例混合,即可将其和自修复行为一起转化为氧化的海藻酸钠基水凝胶。
Oxidized sodium alginate is a handily modifiable polysaccharide owing to the pendant aldehyde groups which can form dynamic covalent bonds with amines, acylhydrazines, etc., providing oxidized sodium alginate-based hydrogels with stimuli-responsive properties. However, due to the stiffness and, in particular, the hydrophobicity of sodium alginate dialdehyde at low pH, the mechanical performance and pH stimuli responsiveness of oxidized sodium alginate-based hydrogels are still strictly limited. Herein, we report a new strategy to build an injectable, dual responsive, and self-healing hydrogel based on oxidized sodium alginate and hydrazide-modified poly(ethyleneglycol) (PEG). The hydrazide-modified PEG, referred to as PEG-DTP, acts as a macromolecule crosslinker. We found that the presence of PEG-DTP reduces the hydrophobicity of oxidized sodium alginate at low pH so effectively that even a pH-induced reversible sol-gel transitions can be realized. Meanwhile, the disulfide bonds in PEG-DTP endows the hydrogel with the other reversible sol-gel transitions by redox stimuli. In particular, due to the softness of PEG-DTP chains, mechanical performance was also enhanced significantly. Our results indicate we can easily integrate multi-stimuli responsiveness, injectability, and self-healing behavior together into an oxidized sodium alginate-based hydrogel merely by mixing an oxidized sodium alginate solution with PEG-DTP solution in certain proportions.