Hybrid hydrogels based on silylated polyethylene glycol, Si-PEG, were evaluated as hybrid matrices able to trap, stabilize and release bovine serum albumin (BSA) in a controlled manner. Parameters of the inorganic condensation reaction leading to a siloxane (Si–O–Si) three dimensional network were carefully investigated, in particular the temperature, the surrounding hygrometry and the Si-PEG concentration. The resulting hydrogel structural features affected the stability, swelling, and mechanical properties of the network, leading to different protein release profiles. Elongated polymer assemblies were observed, the length of which ranged from 150 nm to over 5 μm. The length could be correlated to the Si–O–Si condensation rate from 60% (hydrogels obtained at 24 °C) to about 90% (xerogels obtained at 24 °C), respectively. Consequently, the controlled release of BSA could be achieved from hours to several weeks, with respect to the fibers' length and the condensation rate. The protein stability was evaluated by means of a thermal study. The main results gave insight into the biomolecule structure preservation during polymerisation, with ΔG < 0 for encapsulated BSA in any conditions, below the melting temperature (65 °C).

中文翻译：

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BSA 在混合 PEG 水凝胶中的封装：稳定性和控释

基于硅烷化聚乙二醇 Si-PEG 的混合水凝胶被评估为能够以受控方式捕获、稳定和释放牛血清白蛋白 (BSA) 的混合基质。仔细研究了导致硅氧烷 (Si-O-Si) 三维网络的无机缩合反应的参数，特别是温度、周围湿度和 Si-PEG 浓度。由此产生的水凝胶结构特征会影响网络的稳定性、膨胀和机械性能，从而导致不同的蛋白质释放曲线。观察到伸长的聚合物组件，其长度范围从 150 nm 到超过 5 μm。长度可以分别与从 60%（在 24 °C 下获得的水凝胶）到约 90%（在 24 °C 下获得的干凝胶）的 Si-O-Si 缩合率相关。最后，BSA 的受控释放可以在数小时到数周内实现，就纤维的长度和缩合率而言。通过热研究评估蛋白质稳定性。主要结果深入了解了聚合过程中生物分子结构的保存，Δ对于封装的 BSA， G < 0 在任何条件下，低于熔化温度 (65 °C)。