Thomas Jessica A, Balzer Alex H, Kalidindi Subhash, Korley LaShanda T J
Materials Science and Engineering, University of Delaware Newark DE 19716 USA
Chemical and Biomolecular Engineering, University of Delaware Newark DE 19716 USA.
Mol Syst Des Eng. 2025 Jun 2. doi: 10.1039/d5me00009b.
Taking inspiration from natural systems, such as spider silk and mollusk nacre, that employ hierarchical assembly to attain robust material performance, we leveraged matrix-filler interactions within reinforced polymer-peptide hybrids to create self-assembled hydrogels with enhanced properties. Specifically, cellulose nanocrystals (CNCs) were incorporated into peptide-polyurea (PPU) hybrid matrices to tailor key hydrogel features through matrix-filler interactions. Herein, we examined the impact of peptide repeat length and CNC loading on hydrogelation, morphology, mechanics, and thermal behavior of PPU/CNC composite hydrogels. The addition of CNCs into PPU hydrogels resulted in increased gel stiffness; however, the extent of reinforcement of the nanocomposite gels upon nanofiller inclusion also was driven by PPU architecture. Temperature-promoted stiffening transitions observed in nanocomposite PPU hydrogels were dictated by peptide segment length. Analysis of the peptide secondary structure confirmed shifts in the conformation of peptidic domains (α-helices or β-sheets) upon CNC loading. Finally, PPU/CNC hydrogels were probed for their injectability characteristics, demonstrating that nanofiller-matrix interactions were shown to aid rapid network reformation (∼10 s) upon cessation of high shear forces. Overall, this research showcases the potential of modulating matrix-filler interactions within PPU/CNC hydrogels through strategic system design, enabling the tuning of functional hydrogel characteristics for diverse applications.
受自然系统（如蜘蛛丝和软体动物珍珠母）的启发，这些自然系统采用分级组装来获得强大的材料性能，我们利用增强型聚合物 - 肽杂化材料中的基质 - 填料相互作用来创建具有增强性能的自组装水凝胶。具体而言，将纤维素纳米晶体（CNC）掺入肽 - 聚脲（PPU）杂化基质中，通过基质 - 填料相互作用来调整关键的水凝胶特性。在此，我们研究了肽重复长度和CNC负载量对PPU/CNC复合水凝胶的凝胶化、形态、力学和热行为的影响。将CNC添加到PPU水凝胶中导致凝胶硬度增加；然而，纳米填料加入后纳米复合凝胶的增强程度也受PPU结构的驱动。在纳米复合PPU水凝胶中观察到的温度促进的硬化转变由肽段长度决定。对肽二级结构的分析证实了CNC负载后肽结构域（α - 螺旋或β - 片层）构象的变化。最后，对PPU/CNC水凝胶的可注射性特征进行了研究，结果表明纳米填料 - 基质相互作用有助于在高剪切力停止后快速进行网络重构（约10秒）。总体而言，这项研究展示了通过战略系统设计调节PPU/CNC水凝胶中基质 - 填料相互作用的潜力，能够针对不同应用调整功能性水凝胶特性。
