†Department of Chemical Engineering, ‡Department of Chemistry, and §Department of Civil Engineering, Queen's University, Kingston, Ontario Canada K7L 3N6.
Biomacromolecules. 2015 Jul 13;16(7):2040-8. doi: 10.1021/acs.biomac.5b00470. Epub 2015 Jul 2.
Alginate-based amphiphilic graft copolymers were synthesized by single electron transfer living radical polymerization (SET-LRP), forming stable micelles during polymerization induced self-assembly (PISA). First, alginate macroinitiator was prepared by partial depolymerization of native alginate, solubility modification and attachment of initiator. Depolymerized low molecular weight alginate (∼12 000 g/mol) was modified with tetrabutylammonium, enabling miscibility in anhydrous organic solvents, followed by initiator attachment via esterification yielding a macroinitiator with a degree of substitution of 0.02, or 1-2 initiator groups per alginate chain. Then, methyl methacrylate was polymerized from the alginate macroinitiator in mixtures of water and methanol, forming poly(methyl methacrylate) grafts, prior to self-assembly, of ∼75 000 g/mol and polydispersity of 1.2. PISA of the amphiphilic graft-copolymer resulted in the formation of micelles with diameters of 50-300 nm characterized by light scattering and electron microscopy. As the first reported case of LRP from alginate, this work introduces a synthetic route to a preparation of alginate-based hybrid polymers with a precise macromolecular architecture and desired functionalities. The intended application is the preparation of micelles for drug delivery; however, LRP from alginate can also be applied in the field of biomaterials to the improvement of alginate-based hydrogel systems such as nano- and microhydrogel particles, islet encapsulation materials, hydrogel implants, and topical applications. Such modified alginates can also improve the function and application of native alginates in food and agricultural applications.
通过单电子转移活性自由基聚合（SET-LRP）合成了基于海藻酸盐的两亲性接枝共聚物，在聚合诱导自组装（PISA）过程中形成稳定的胶束。首先，通过部分降解天然海藻酸盐、溶解度修饰和连接引发剂制备了海藻酸盐大分子引发剂。将低分子量的降解海藻酸盐（约 12000g/mol）用四丁基铵改性，使其能够在无水有机溶剂中混溶，然后通过酯化反应连接引发剂，得到取代度为 0.02或每个海藻酸盐链 1-2 个引发剂基团的大分子引发剂。然后，在水和甲醇的混合物中从海藻酸盐大分子引发剂聚合甲基丙烯酸甲酯，形成聚（甲基丙烯酸甲酯）接枝，在自组装之前，分子量约为 75000g/mol，多分散性为 1.2。两亲性接枝共聚物的 PISA 导致形成直径为 50-300nm 的胶束，其通过光散射和电子显微镜进行表征。作为海藻酸盐 LRP 的首例报道，这项工作引入了一种从海藻酸盐制备具有精确大分子结构和所需功能的海藻酸盐基杂化聚合物的合成途径。预期的应用是制备用于药物输送的胶束；然而，海藻酸盐的 LRP 也可以应用于生物材料领域，以改善基于海藻酸盐的水凝胶系统，如纳米和微水凝胶颗粒、胰岛包封材料、水凝胶植入物和局部应用。这种改性的海藻酸盐还可以改善天然海藻酸盐在食品和农业应用中的功能和应用。
