在此，提出了一种用于控制药物释放的 pH 响应双交联水凝胶。该水凝胶由可逆硼酸酯键和结晶聚（乙烯醇）构成。通过改变环境pH值，评估凝胶的理化特性，包括流变性能、力学性能、微观结构特征和生物相容性。与生理环境中的凝胶相比，肿瘤酸性条件下的凝胶表现出溶胀以及较低的压缩强度和模量，这归因于PEI聚电解质上的pH响应性硼酸酯键和胺基的质子化。重要的是，药物封装的生物相容性水凝胶在酸性环境下表现出持续和增加的释放，并且遵循菲克扩散机制。因此，它证明了基于硼酸酯键的pH响应性生物材料在生物医学研究，特别是药物输送方面具有广阔的前景。

Herein, a pH-responsive dual cross-linked hydrogel for controlled drug release is presented. The hydrogel was constructed with reversible borate ester bonds and crystalline poly(vinyl alcohol). By changing the environmental pH, its physicochemical characteristics, including rheological properties, mechanical properties, microstructural features, and the biocompatibility of the gels, were evaluated. The gels at tumor acidic conditions exhibited swelling and lower compressive strength and modulus than those in a physiological environment, which was attributed to the pH-responsive borate ester bonds and the protonation of amine groups on the PEI polyelectrolyte. Importantly, the drug-encapsulated biocompatible hydrogel showed sustained and increased release under an acidic environment, and it followed the Fickian diffusion mechanism. Therefore, it exemplifies that borate ester bond-based pH-responsive biomaterials have high promise in biomedical research, especially for drug delivery.