Department of Chemistry, The University of Western Ontario, 1151 Richmond St., London, Ontario N6A 5B7, Canada.
Department of Chemical and Biochemical Engineering, The University of Western Ontario, 1151 Richmond St., London, Ontario N6A 5B9, Canada.
Biomacromolecules. 2023 Aug 14;24(8):3629-3637. doi: 10.1021/acs.biomac.3c00382. Epub 2023 Jul 7.
Hydrogels are of interest for a wide range of applications from sensors to drug delivery and tissue engineering. Self-immolative polymers, which depolymerize from end-to-end following a single backbone or end-cap cleavage, offer advantages such as amplification of the stimulus-mediated cleavage event through a cascade degradation process. It is also possible to change the active stimulus by changing only a single end-cap or linker unit. However, there are very few examples of self-immolative polymer hydrogels, and the reported examples exhibited relatively poor stability in their nontriggered state or slow degradation after triggering. Described here is the preparation of hydrogels composed of self-immolative poly(ethyl glyoxylate) (PEtG) and poly(ethylene glycol) (PEG). Hydrogels formed from 2 kg/mol 4-arm PEG and 1.2 kg/mol PEtG with a light-responsive linker end-cap had high gel content (90%), an equilibrium water content of 89%, and a compressive modulus of 26 kPa. The hydrogel degradation could be turned on and off repeatedly through alternating cycles of irradiation and dark storage. Similar cycles could also be used to control the release of the anti-inflammatory drug celecoxib. These results demonstrate the potential for self-immolative hydrogels to afford a high degree of control over responses to stimuli in the context of smart materials for a variety of applications.
水凝胶在传感器、药物输送和组织工程等广泛的应用中都很有意义。自焚性聚合物在单一主链或端帽断裂后从端到端解聚，具有通过级联降解过程放大刺激介导的断裂事件的优点。通过仅改变单个端帽或连接单元，也可以改变活性刺激物。然而，自焚性聚合物水凝胶的例子非常少，并且报道的例子在未触发状态下表现出相对较差的稳定性，或者在触发后降解缓慢。这里描述的是由自焚性聚(乙二醛)(PEtG)和聚(乙二醇)(PEG)组成的水凝胶的制备。由 2kg/mol 四臂 PEG 和 1.2kg/mol PEtG 与光响应连接帽组成的水凝胶具有高凝胶含量(90%)、平衡水含量 89%和压缩模量 26kPa。水凝胶的降解可以通过交替的辐照和暗存储循环来反复开启和关闭。类似的循环也可用于控制抗炎药物塞来昔布的释放。这些结果表明，自焚性水凝胶在智能材料中为各种应用提供了对刺激物响应的高度控制，具有很大的潜力。
