Electrostatic interactions play a significant role in regulating biological systems and have received increasing attention due to their usefulness in designing advanced stimulus-responsive materials. Polypeptoids are highly tunable N-substituted peptidomimetic polymers that lack backbone hydrogen bonding and chirality. Therefore, polypeptoids are suitable systems to study the effect of noncovalent interactions of substituents without complications of backbone intramolecular and intermolecular hydrogen bonding. In this study, all-atom molecular dynamics (MD) simulations were performed on micelles formed by a series of sequence-defined ionic polypeptoid block copolymers consisting of a hydrophobic segment and a hydrophilic segment in an aqueous solution. By combining the results from MD simulations and experimental small-angle neutron scattering data, further insights were gained into the internal structure of the formed polypeptoid micelles, which is not always directly accessible from experiments. In addition, information was gained into the physics of the noncovalent interactions responsible for the self-assembly of weakly charged polypeptoids in an aqueous solution. While the aggregation number is governed by electrostatic repulsion of the negatively charged carboxylate (COO^–) substituents on the polypeptoid chain within the micelle, MD simulations indicate that the position of the charge on singly charged chains mediates the shape of the micelle through the charge–dipole interactions between the COO^– substituent and the surrounding water. Therefore, the polypeptoid micelles formed from the single-charged series offer the possibility for tailorable micelle shapes. In contrast, the polypeptoid micelles formed from the triple-charged series are characterized by more pronounced electrostatic repulsion that competes with more significant charge–sodium interactions, making it difficult to predict the shape of the micelles. This work has helped further develop design principles for the shape and structure of self-assembled micelles by controlling the position of charged moieties on the backbone of polypeptoid block copolymers.

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通过分子动力学模拟揭示电荷图案化在序列定义的两亲类肽低聚物的胶束结构中的作用

静电相互作用在调节生物系统方面发挥着重要作用，并且由于它们在设计先进的刺激响应材料方面的有用性而受到越来越多的关注。多肽是高度可调的 N 取代肽模拟聚合物，缺乏主链氢键和手性。因此，多肽类是研究取代基非共价相互作用的影响的合适系统，而不会出现骨架分子内和分子间氢键的并发症。在这项研究中，对由一系列序列定义的离子多肽嵌段共聚物形成的胶束进行了全原子分子动力学 (MD) 模拟，该嵌段共聚物由水溶液中的疏水链段和亲水链段组成。通过结合 MD 模拟的结果和实验小角中子散射数据，对形成的多肽类胶束的内部结构获得了进一步的了解，而这并不总是可以直接从实验中获得。此外，还获得了非共价相互作用的物理信息，这些相互作用负责在水溶液中自组装弱电荷多肽。而聚集数由带负电荷的羧酸盐（COO 获得了有关在水溶液中自组装弱电荷多肽的非共价相互作用的物理学信息。而聚集数由带负电荷的羧酸盐（COO 获得了有关在水溶液中自组装弱电荷多肽的非共价相互作用的物理学信息。而聚集数由带负电荷的羧酸盐（COO^– ) 胶束内多肽链上的取代基，MD 模拟表明，单电荷链上的电荷位置通过 COO 之间的电荷-偶极相互作用介导胶束的形状^–取代基和周围的水。因此，由单电荷系列形成的多肽类胶束为可定制的胶束形状提供了可能性。相比之下，由三电荷系列形成的多肽胶束的特点是更明显的静电排斥，与更显着的电荷 - 钠相互作用竞争，使得难以预测胶束的形状。这项工作通过控制多肽嵌段共聚物主链上带电部分的位置，有助于进一步发展自组装胶束的形状和结构的设计原则。