Material Science and Engineering Interdisciplinary Program, Texas A&M University, College Station, Texas 77843, United States.
Biomacromolecules. 2011 Oct 10;12(10):3629-37. doi: 10.1021/bm200889k. Epub 2011 Sep 15.
Incorporation of nanoparticles during the hierarchical self-assembly of protein-based materials can impart function to the resulting composite materials. Herein we demonstrate that the structure and nanoparticle distribution of composite fibers are sensitive to the method of nanoparticle addition and the physicochemical properties of both the nanoparticle and the protein. Our model system consists of a recombinant enhanced green fluorescent protein-Ultrabithorax (EGFP-Ubx) fusion protein and luminescent CdSe-ZnS core-shell quantum dots (QDs), allowing us to optically assess the distribution of both the protein and nanoparticle components within the composite material. Although QDs favorably interact with EGFP-Ubx monomers, the relatively rough surface morphology of composite fibers suggests EGFP-Ubx-QD conjugates impact self-assembly. Indeed, QDs templated onto EGFP-Ubx film post-self-assembly can be subsequently drawn into smooth composite fibers. Additionally, the QD surface charge impacts QD distribution within the composite material, indicating that surface charge plays an important role in self-assembly. QDs with either positively or negatively charged coatings significantly enhance fiber extensibility. Conversely, QDs coated with hydrophobic moieties and suspended in toluene produce composite fibers with a heterogeneous distribution of QDs and severely altered fiber morphology, indicating that toluene severely disrupts Ubx self-assembly. Understanding factors that impact the protein-nanoparticle interaction enables manipulation of the structure and mechanical properties of composite materials. Since proteins interact with nanoparticle surface coatings, these results should be applicable to other types of nanoparticles with similar chemical groups on the surface.
在基于蛋白质的材料的分级自组装过程中掺入纳米粒子可以赋予所得复合材料功能。在此，我们证明了复合纤维的结构和纳米粒子分布对纳米粒子添加方法以及纳米粒子和蛋白质的物理化学性质都很敏感。我们的模型系统由重组增强型绿色荧光蛋白-Ultrabithorax（EGFP-Ubx）融合蛋白和发光 CdSe-ZnS 核壳量子点（QD）组成，使我们能够光学评估复合材料中蛋白质和纳米粒子成分的分布。尽管 QD 与 EGFP-Ubx 单体有利相互作用，但复合纤维的相对粗糙的表面形态表明 EGFP-Ubx-QD 缀合物影响自组装。事实上，在自组装后可以将 QD 模板化到 EGFP-Ubx 膜上，然后将其拉成光滑的复合纤维。此外，QD 的表面电荷会影响复合材料中 QD 的分布，表明表面电荷在自组装中起着重要作用。带有正电荷或负电荷涂层的 QD 大大提高了纤维的延展性。相反，带有疏水性部分并悬浮在甲苯中的 QD 会产生具有不均匀 QD 分布和严重改变纤维形态的复合纤维，表明甲苯严重破坏了 Ubx 自组装。了解影响蛋白质-纳米粒子相互作用的因素可以控制复合材料的结构和机械性能。由于蛋白质与纳米粒子表面涂层相互作用，这些结果应该适用于具有类似表面化学基团的其他类型的纳米粒子。
