Pardy Jared D, Tavsanli Burak, Sirianni Quinton E A, Gillies Elizabeth R
School of Biomedical Engineering, The University of Western Ontario, 1151 Richmond Street, N6A 5B9, London, Ontario, Canada.
Department of Chemistry, The University of Western Ontario, 1151 Richmond St., N6A 5B7, London, Ontario, Canada.
Chemistry. 2024 Aug 22;30(47):e202401324. doi: 10.1002/chem.202401324. Epub 2024 Aug 5.
Hydrogels are of interest for a wide range of applications. The ability to control when the hydrogel degrades can provide beneficial properties such as controlled degradation in the environment or the stimulated release of drugs or cells. Self-immolative polymers are a class of degradable polymers that undergo complete end-to-end depolymerization upon the application of a stimulus. They have been explored for hydrogel development, but the ability to prepare and selectively degrade self-immolative hydrogels under neutral aqueous conditions has so far been limited. We describe here the preparation of water-soluble polyglyoxylamides with cross-linkable pendent azides and their cross-linking to form hydrogels with 4-arm poly(ethylene glycol)s having unstrained and strained alkynes using copper-assisted and strain-promoted azide-alkyne click chemistry respectively. The influence of pendent azide density and solution polymer content on the resulting hydrogels was evaluated. A polyglyoxylamide with a 70 : 30 ratio of pendent hydroxyl:azide successfully provided hydrogels with compressive moduli ranging from 1.3-6.3 kPa under copper-free conditions at 10-20 % (w/w) of polymer in phosphate-buffered saline. Selective depolymerization and degradation of the hydrogels upon irradiation with light was demonstrated, resulting in reductions in the compressive moduli and the release of depolymerization products that were detected by NMR spectroscopy.
水凝胶在广泛的应用领域中备受关注。控制水凝胶何时降解的能力可提供有益特性，例如在环境中的可控降解或药物或细胞的刺激释放。自牺牲聚合物是一类可降解聚合物，在施加刺激时会发生完全的端到端解聚。它们已被用于水凝胶开发，但迄今为止，在中性水性条件下制备和选择性降解自牺牲水凝胶的能力仍然有限。我们在此描述了具有可交联侧基叠氮化物的水溶性聚乙二醛酰胺的制备，以及它们分别使用铜辅助和应变促进的叠氮化物-炔烃点击化学与具有未受应变和受应变炔烃的四臂聚乙二醇交联形成水凝胶的过程。评估了侧基叠氮化物密度和溶液聚合物含量对所得水凝胶的影响。一种侧基羟基与叠氮化物比例为70:30的聚乙二醛酰胺在无铜条件下，于磷酸盐缓冲盐水中聚合物含量为10-20%（w/w）时成功提供了压缩模量范围为1.3 - 6.3 kPa的水凝胶。证明了水凝胶在光照下的选择性解聚和降解，导致压缩模量降低，并释放出通过核磁共振光谱检测到的解聚产物。
