Department of Molecular Biology and Plant Virology, Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany.
Institute of Solid State Physics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
Beilstein J Nanotechnol. 2015 Jun 25;6:1399-412. doi: 10.3762/bjnano.6.145. eCollection 2015.
The coating of regular-shaped, readily available nanorod biotemplates with inorganic compounds has attracted increasing interest during recent years. The goal is an effective, bioinspired fabrication of fiber-reinforced composites and robust, miniaturized technical devices. Major challenges in the synthesis of applicable mineralized nanorods lie in selectivity and adjustability of the inorganic material deposited on the biological, rod-shaped backbones, with respect to thickness and surface profile of the resulting coating, as well as the avoidance of aggregation into extended superstructures. Nanotubular tobacco mosaic virus (TMV) templates have proved particularly suitable towards this goal: Their multivalent protein coating can be modified by high-surface-density conjugation of peptides, inducing and governing silica deposition from precursor solutions in vitro. In this study, TMV has been equipped with mineralization-directing peptides designed to yield silica coatings in a reliable and predictable manner via precipitation from tetraethoxysilane (TEOS) precursors. Three peptide groups were compared regarding their influence on silica polymerization: (i) two peptide variants with alternating basic and acidic residues, i.e. lysine-aspartic acid (KD) x motifs expected to act as charge-relay systems promoting TEOS hydrolysis and silica polymerization; (ii) a tetrahistidine-exposing polypeptide (CA4H4) known to induce silicification due to the positive charge of its clustered imidazole side chains; and (iii) two peptides with high ZnO binding affinity. Differential effects on the mineralization of the TMV surface were demonstrated, where a (KD) x charge-relay peptide (designed in this study) led to the most reproducible and selective silica deposition. A homogenous coating of the biotemplate and tight control of shell thickness were achieved.
近年来，人们对使用常规形状、易于获得的纳米棒生物模板来涂覆无机化合物越来越感兴趣。其目的是有效地模仿生物制造纤维增强复合材料和坚固、小型化的技术设备。在合成适用的矿化纳米棒方面，主要的挑战在于所沉积的无机材料在生物、棒状骨架上的选择性和可调节性，以及所得到的涂层的厚度和表面轮廓，以及避免聚集为扩展的超结构。管状烟草花叶病毒（TMV）模板在这方面被证明是特别合适的：它们的多价蛋白质涂层可以通过高表面密度的肽偶联进行修饰，从而在体外从前体溶液中诱导和控制二氧化硅的沉积。在这项研究中，TMV 被配备了矿化导向肽，这些肽旨在通过从四乙氧基硅烷（TEOS）前体中沉淀的方式可靠且可预测地产生二氧化硅涂层。比较了三个肽组对二氧化硅聚合的影响：（i）两种具有交替的碱性和酸性残基的肽变体，即赖氨酸-天冬氨酸（KD）x 基序，预计作为电荷传递系统促进 TEOS 水解和二氧化硅聚合；（ii）一种暴露四组氨酸的多肽（CA4H4），由于其聚集的咪唑侧链的正电荷而被认为能诱导硅化；（iii）两种与 ZnO 结合亲和力高的肽。证明了对 TMV 表面矿化的影响存在差异，其中（KD）x 电荷传递肽（在本研究中设计）导致了最具重现性和选择性的二氧化硅沉积。实现了生物模板的均匀涂层和壳层厚度的紧密控制。
