Poly(2-alkyl-2-oxazoline) (PAOx) hydrogels are tailorable synthetic materials with demonstrated biomedical applications, thanks to their excellent biocompatibility and tunable properties. However, their use as injectable hydrogels is challenging as it requires invasive surgical procedures to insert the formed hydrogel into the body due to their nonsoluble 3D network structures. Herein, we introduce cyclooctyne and azide functional side chains to poly(2-oxazoline) copolymers to induce in situ gelation using strain promoted alkyne–azide cycloaddition. The gelation occurs rapidly, within 5 min, under physiological conditions when two polymer solutions are simply mixed. The influence of several parameters, such as temperature and different aqueous solutions, and stoichiometric ratios between the two polymers on the structural properties of the resultant hydrogels have been investigated. The gel formation within tissue samples was verified by subcutaneous injection of the polymer solution into an ex vivo model. The degradation study of the hydrogels in vitro showed that the degradation rate was highly dependent on the type of media, ranging from days to a month. This result opens up the potential uses of PAOx hydrogels in attempts to achieve optimal, injectable drug delivery systems and tissue engineering.

中文翻译：

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可注射的生物相容性聚（2-恶唑啉）水凝胶通过应变促进炔-叠氮化物环加成

聚（2-烷基-2-恶唑啉）（PAOx）水凝胶是可定制的合成材料，由于其出色的生物相容性和可调节的特性，在生物医学应用中得到了证明。然而，它们作为可注射水凝胶的使用具有挑战性，因为由于其不可溶的 3D 网络结构，它需要侵入性外科手术才能将形成的水凝胶插入体内。在此，我们将环辛炔和叠氮化物功能侧链引入聚（2-恶唑啉）共聚物以原位诱导使用应变促进炔-叠氮化物环加成的凝胶化。在生理条件下，当两种聚合物溶液简单混合时，凝胶会在 5 分钟内迅速发生。已经研究了几个参数，例如温度和不同的水溶液，以及两种聚合物之间的化学计量比对所得水凝胶的结构特性的影响。通过将聚合物溶液皮下注射到离体模型中来验证组织样品中的凝胶形成。水凝胶体外降解研究表明降解率高度依赖于介质的类型，从几天到一个月不等。这一结果开辟了 PAOx 水凝胶在尝试实现最佳、可注射给药系统和组织工程方面的潜在用途。