Departamento de Polímeros y Materiales Avanzados, Física, Química y Tecnología, University of the Basque Country (UPV/EHU), Apartado 1072, 20080 San Sebastián, Spain.
Soft Matter. 2020 Nov 4;16(42):9738-9745. doi: 10.1039/d0sm01447h.
Single-chain polymer nanoparticles (SCNPs) are soft nano-objects consisting of uni-macromolecular chains collapsed to a certain degree by intramolecular crosslinking. The similarities between the behaviour of SCNPs and that of intrinsically disordered proteins suggest that SCNPs in concentrated solutions can be used as models to design artificial micro-environments, which mimic many of the general aspects of cellular environments. In this work, the self-assembly into SCNPs of an amphiphilic random copolymer, composed by oligo(ethylene glycol)methyl ether methacrylate (OEGMA) and 2-acetoacetoxy ethyl methacrylate (AEMA), has been investigated by means of the dielectric relaxation of water. Direct evidence of segregation of the AEMA repeating units is provided by comparison with the dielectric relaxation of water in similar solutions of the linear hydrophilic polymer, P(OEGMA). Furthermore, the results of comparative studies with similar water solutions of an amphiphilic block copolymer forming multi-chain micelles support the single-chain character of the self-assembly of the random copolymer. The overall obtained results highlight the suitability of the dielectric spectroscopy to confirm the self-assembly of the amphiphilic random copolymers into globular like core-shell single-chain nanoparticles at a concentration well above the overlap concentration.
单链聚合物纳米粒子（SCNPs）是由单分子链通过分子内交联而在一定程度上坍塌形成的软纳米物体。SCNPs 的行为与无规卷曲蛋白质的行为相似，这表明在高浓度溶液中的 SCNPs 可以用作设计人工微环境的模型，模拟细胞环境的许多一般方面。在这项工作中，通过水的介电弛豫研究了由聚乙二醇甲基醚甲基丙烯酸酯（OEGMA）和 2-乙酰乙酰氧基乙基甲基丙烯酸酯（AEMA）组成的两亲性无规共聚物自组装成 SCNPs。通过与类似的线性亲水性聚合物 P（OEGMA）的水介电弛豫的比较，提供了 AEMA 重复单元的分离的直接证据。此外，与形成多链胶束的类似两亲嵌段共聚物的水相比较研究的结果支持了无规共聚物自组装成单链纳米颗粒的单链特性。总体获得的结果强调了介电光谱法适用于在超过重叠浓度的浓度下确认两亲无规共聚物自组装成类球形核壳单链纳米颗粒。
