Graduate School of Engineering, Oita University, 700 Dannoharu, Oita 870-1192, Japan.
Research Promotion Institute, Oita University, 700 Dannoharu, Oita 870-1192, Japan.
Langmuir. 2021 Dec 21;37(50):14760-14766. doi: 10.1021/acs.langmuir.1c02809. Epub 2021 Dec 10.
Transformable double hydrophilic block copolymer assemblies are valid as a biocompatible smart macromolecular system. The molecular mechanisms in the spontaneous assembly of double zwitterionic diblock copolymers composed of a poly(carboxybetaine methacrylate) (PCB2) and a poly(sulfobetaine methacrylate) (PSB4) chains (PCB2--PSB4) were investigated by the modulation of the aggregates in response to nondetergent zwitterions. The PCB2--PSB4 diblock copolymers with a high degree of polymerization PSB4 block produced aggregates in salt-free water through "zwitterion-specific" interactions. The PCB2--PSB4 aggregates were dissociated by the addition of nondetergent sulfobetaine (SB4) and carboxybetaine (CB2) molecules, while the aggregates showed different aggregation modulation processes for SB4 and CB2. Zwitterions with different charged groups from SB4 and CB2, glycine and taurine, hardly disrupted the PCB2--PSB4 aggregates. The PCB2--PSB4 aggregate modulation efficiency of SBs associated with the intercharge hydrocarbon spacer length (CSL) rather than the symmetry with the SB in the PSB chain. These zwitterion-specific modulation behaviors were rationalized based on the nature of zwitterions including partial charge density, dipole moment, and hydrophobic interactions depending on the charged groups and CSL.
可变形的双亲水性嵌段共聚物组装体是一种具有生物相容性的智能高分子体系。通过调节非离子型两性离子对聚集物的响应，研究了由聚（羧基甜菜碱甲基丙烯酸酯）（PCB2）和聚（磺基甜菜碱甲基丙烯酸酯）（PSB4）链组成的双离子型两亲嵌段共聚物（PCB2-PSB4）自发组装的分子机制。具有高聚合度 PSB4 嵌段的 PCB2-PSB4 两亲嵌段共聚物在无盐水中通过“两性离子特异性”相互作用产生聚集物。通过添加非离子型两性离子磺基甜菜碱（SB4）和羧基甜菜碱（CB2）分子，PCB2-PSB4 聚集物被解离，而聚集物对 SB4 和 CB2 表现出不同的聚集调节过程。与 SB4 和 CB2 具有不同带电基团的甘氨酸和牛磺酸几乎不会破坏 PCB2-PSB4 聚集物。与 PSB 链中的 SB 具有对称性相比，与 SBs 相关的 PCB2-PSB4 聚集物调节效率与 SBs 中的内电荷烃间隔基长度（CSL）有关。这些两性离子特异性调节行为基于两性离子的性质进行了合理化解释，包括部分电荷密度、偶极矩和疏水性相互作用，这取决于带电基团和 CSL。
