Abstract Redox and pH responsive hydrogels were synthesized, which can serve as matrices for smart drug delivery systems exploiting the redox and pH gradients in the human body. Water soluble thiolated poly(aspartic acid), a biocompatible synthetic polymer, enables us to cross-link in water with a non-cleavable cross-linker, poly(ethylene glycol) diglycidyl ether. The permanent cross-linker establishes stable polymer hydrogels regardless of the redox environment, thus the gels swell but do not dissolve upon redox stimuli. The reversible response upon redox stimulus was induced by thiol-disulphide transformation inside the hydrogel. The degree of swelling and the stiffness of the macroscopic hydrogels were controlled by their chemical composition including thiol content and cross-linking ratio as well as the redox state of the hydrogels. The degree of swelling of the hydrogels showed strong pH dependence due to the polyelectrolyte nature of the polymer network. Release of a macromolecular model drug was considerably faster in reducing than in oxidising environment, which indicates the potential use of the synthesized hydrogels as redox responsive drug delivery systems. Nanogels were prepared in water-in-oil emulsion and displayed redox-responsive properties. The hydrodynamic diameter of the nanogels strongly increased upon the cleavage of the disulphide linkages in reducing solution without the disruption of the gels.

中文翻译：

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聚（天冬氨酸）水凝胶在氧化还原刺激下表现出可逆的体积变化

摘要 合成了氧化还原和 pH 响应水凝胶，可用作利用人体氧化还原和 pH 梯度的智能药物递送系统的基质。水溶性硫醇化聚（天冬氨酸）是一种生物相容性合成聚合物，使我们能够在水中与不可裂解的交联剂聚（乙二醇）二缩水甘油醚交联。无论氧化还原环境如何，永久交联剂都能建立稳定的聚合物水凝胶，因此凝胶会膨胀但不会在氧化还原刺激下溶解。氧化还原刺激的可逆反应是由水凝胶内的硫醇-二硫化物转化引起的。宏观水凝胶的溶胀度和刚度受其化学成分控制，包括硫醇含量和交联比以及水凝胶的氧化还原状态。由于聚合物网络的聚电解质性质，水凝胶的溶胀程度显示出强烈的 pH 依赖性。大分子模型药物的释放在还原环境中比在氧化环境中快得多，这表明合成的水凝胶作为氧化还原响应药物递送系统的潜在用途。纳米凝胶在油包水乳液中制备，并显示出氧化还原响应特性。在还原溶液中二硫键断裂后，纳米凝胶的流体动力学直径大大增加，而凝胶不会被破坏。这表明合成的水凝胶作为氧化还原响应药物递送系统的潜在用途。纳米凝胶在油包水乳液中制备，并显示出氧化还原响应特性。在还原溶液中二硫键断裂后，纳米凝胶的流体动力学直径大大增加，而凝胶不会被破坏。这表明合成的水凝胶作为氧化还原响应药物递送系统的潜在用途。纳米凝胶在油包水乳液中制备，并显示出氧化还原响应特性。在还原溶液中二硫键断裂后，纳米凝胶的流体动力学直径大大增加，而凝胶不会被破坏。