Matei Iulia, Ariciu Ana-Maria, Popescu Elena Irina, Mocanu Sorin, Neculae Alexandru Vincentiu Florian, Savonea Florenta, Ionita Gabriela
"Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania.
IPG Health Consulting, King Edward Street, Macclesfield SK19 1AQ, UK.
Gels. 2022 Jul 8;8(7):428. doi: 10.3390/gels8070428.
In this work, we explored by means of electron paramagnetic resonance (EPR) spectroscopy the accessibility of a series of spin probes, covering a scale of molecular weights in the range of 200-60,000 Da, in a variety of hydrogels: covalent network, ionotropic, interpenetrating polymer network (IPN) and semi-IPN. The covalent gel network consists of polyethylene or polypropylene chains linked isocyanate groups with cyclodextrin, and the ionotropic gel is generated by alginate in the presence of Ca ions, whereas semi-IPN and IPN gel networks are generated in a solution of alginate and chitosan by adding crosslinking agents, Ca for alginate and glutaraldehyde for chitosan. It was observed that the size of the diffusing species determines the ability of the gel to uptake them. Low molecular weight compounds can diffuse into the gel, but when the size of the probes increases, the gel cannot uptake them. Spin-labelled Pluronic F127 cannot be encapsulated by any covalent gel, whereas spin-labelled albumin can diffuse in alginate gels and in most of the IPN networks. The EPR spectra also evidenced the specific interactions of spin probes inside hydrogels. The results suggest that EPR spectroscopy can be an alternate method to evaluate the mesh size of gel systems and to provide information on local interactions inside gels.
在这项工作中，我们通过电子顺磁共振（EPR）光谱法，研究了一系列分子量在200至60,000 Da范围内的自旋探针在多种水凝胶中的可及性，这些水凝胶包括：共价网络凝胶、离子型凝胶、互穿聚合物网络（IPN）凝胶和半互穿聚合物网络（semi - IPN）凝胶。共价凝胶网络由通过异氰酸酯基团与环糊精相连的聚乙烯或聚丙烯链组成，离子型凝胶是在钙离子存在下由藻酸盐生成的，而半互穿聚合物网络凝胶和互穿聚合物网络凝胶是在藻酸盐和壳聚糖的溶液中通过添加交联剂生成的，藻酸盐用钙离子交联，壳聚糖用戊二醛交联。观察到扩散物质的大小决定了凝胶吸收它们的能力。低分子量化合物能够扩散到凝胶中，但当探针尺寸增大时，凝胶无法吸收它们。自旋标记的普朗尼克F127不能被任何共价凝胶包封，而自旋标记的白蛋白能够在藻酸盐凝胶和大多数互穿聚合物网络中扩散。EPR光谱还证明了水凝胶内部自旋探针的特异性相互作用。结果表明，EPR光谱法可以作为一种评估凝胶体系网孔大小以及提供凝胶内部局部相互作用信息的替代方法。
