Structure–mechanics relationship of hybrid polyvinyl alcohol-collagen composite by molecular dynamics simulations
Structure–mechanics relationship of hybrid polyvinyl alcohol-collagen composite by molecular dynamics simulations
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DOI：
10.1557/s43577-022-00416-0
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发表时间：
2022-11
期刊：
影响因子：
5
通讯作者：
Ju-ying Zhou;Zhao Qin
中科院分区：
文献类型：
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作者：
Ju-ying Zhou;Zhao Qin
摘要聚乙烯醇（PVA）是一种水溶性合成聚合物，可用于制造生物医学应用的水凝胶以及生物降解袋和薄膜;然而，与目前用于容器的其他塑料相比，它缺乏机械强度，热稳定性，并且容易从潮湿环境中吸收水分。虽然通过在混合水凝胶中混合PVA与胶原蛋白已经观察到机械改善，但是缺乏对分子机制的基本理解，并且不清楚改善是否限于水合状态。在这里，使用经典的分子动力学模拟的基础上完全原子模型，我们开发的PVA与胶原蛋白的平衡分子结构和表征其力学。我们发现，通过与胶原蛋白分子的相互作用，PVA平衡到一个更有序的结构，每个残基与附近的邻居通过形成更多的氢键局部相互作用，使结构比纯PVA更硬。该结构在熔融前显示出较高的热稳定性，以及在水中的较高刚性。我们的研究结果提供了混合PVA-胶原聚合物的机械优势的机制。这项研究表明，合成聚合物的结构和力学可以通过分子界面上的少量天然聚合物来调节。此外，它可能有助于找到一种方法来改善可生物降解聚合物材料的力学性能，而不会增加太多成本，这对环境安全至关重要。混合天然和合成聚合物（例如，混合水凝胶中的聚乙烯醇[PVA]和胶原蛋白）在聚合物力学方面显示出优势，但缺乏基本的理解。使用分子动力学（MD）模拟的基础上完全原子模型，我们开发的PVA与胶原蛋白的平衡结构和表征其力学。我们发现，通过与胶原蛋白分子的相互作用，PVA平衡到一个更有序的结构，每个残基与附近的邻居通过形成更多的H-键局部和结构比纯PVA更硬。此外，该结构在PVA的熔点之前显示出较高的热稳定性，以及在水中的较高刚性。我们的研究结果表明，合成聚合物的结构和力学可以通过在分子界面处的少量天然聚合物来调节。它提供了实验观察到的机械优势的机制。该研究为杂化高分子材料的多尺度建模和力学设计奠定了基础。它揭示了一种方法来改善生物可降解材料的力学性能，而不会为材料功能和环境安全增加太多成本。图形摘要
Abstract Polyvinyl alcohol (PVA) is a water-soluble synthetic polymer that can be used to make hydrogels for biomedical applications as well as biodegradable bags and films; however, compared to other plastics currently used for containers, it lacks mechanical strength, thermal stability, and can easily absorb water from humid environments. Although mechanical improvement has been observed by blending PVA with collagen in a hybrid hydrogel, there is a lack of fundamental understanding of the molecular mechanism, and it is not clear whether the improvement is limited to a hydrated state. Here, using classical molecular dynamics simulations based on fully atomistic models, we develop the equilibrated molecular structure of PVA with collagen and characterize its mechanics. We show that by interacting with a collagen molecule, PVA is equilibrated to a more ordered structure with each residue interacting with the near neighbors by forming more hydrogen bonds locally, making the structure stiffer than pure PVA. The structure shows higher thermal stability before melting, as well as higher rigidity in water. Our results provide the mechanism of the mechanical advantages of hybrid PVA-collagen polymer. The study demonstrates that the structure and mechanics of a synthetic polymer can be tuned by a tiny amount of a natural polymer at the molecular interface. Moreover, it may shed light on identifying a way to improve the mechanics of biodegradable polymer materials without adding much cost, which is crucial for environmental safety. Impact statement Blending natural and synthetic polymers (e.g., polyvinyl alcohol [PVA] and collagen in a hybrid hydrogel) has shown advantages in polymer mechanics, but there is a lack of fundamental understanding. Using molecular dynamics (MD) simulations based on fully atomistic models, we develop the equilibrated structure of the PVA with collagen and characterize its mechanics. We show that by interacting with a collagen molecule, PVA is equilibrated to a more ordered structure with each residue interacting with the near neighbors by forming more H-bonds locally and the structure is stiffer than pure PVA. Moreover, the structure shows a higher thermal stability before the melting point of PVA, as well as higher rigidity in water. Our results demonstrate that the structure and mechanics of a synthetic polymer can be tuned by a tiny amount of a natural polymer at the molecular interface. It provides the mechanism of the mechanical advantages as experimentally observed. This study paves the way for the multiscale modeling and mechanical design of the hybrid polymer material. It sheds light on identifying a way to improve the mechanics of biodegradable materials without adding much cost for both material functionality and environmental safety. Graphical abstract