Helmholtz-Institute Freiberg for Resource Technology, Helmholtz-Zentrum Dresden-Rossendorf, 01314, Dresden, Germany.
Microb Cell Fact. 2012 Dec 23;11:163. doi: 10.1186/1475-2859-11-163.
Escherichia coli is one of the best studied microorganisms and finds multiple applications especially as tool in the heterologous production of interesting proteins of other organisms. The heterologous expression of special surface (S-) layer proteins caused the formation of extremely long E. coli cells which leave transparent tubes when they divide into single E. coli cells. Such natural structures are of high value as bio-templates for the development of bio-inorganic composites for many applications. In this study we used genetically modified filamentous Escherichia coli cells as template for the design of polyelectrolyte tubes that can be used as carrier for functional molecules or particles. Diversity of structures of biogenic materials has the potential to be used to construct inorganic or polymeric superior hybrid materials that reflect the form of the bio-template. Such bio-inspired materials are of great interest in diverse scientific fields like Biology, Chemistry and Material Science and can find application for the construction of functional materials or the bio-inspired synthesis of inorganic nanoparticles.
Genetically modified filamentous E. coli cells were fixed in 2% glutaraldehyde and coated with alternating six layers of the polyanion polyelectrolyte poly(sodium-4styrenesulfonate) (PSS) and polycation polyelectrolyte poly(allylamine-hydrochloride) (PAH). Afterwards we dissolved the E. coli cells with 1.2% sodium hypochlorite, thus obtaining hollow polyelectrolyte tubes of 0.7 μm in diameter and 5-50 μm in length. For functionalisation the polyelectrolyte tubes were coated with S-layer protein polymers followed by metallisation with Pd(0) particles. These assemblies were analysed with light microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy.
The thus constructed new material offers possibilities for diverse applications like novel catalysts or metal nanowires for electrical devices. The novelty of this work is the use of filamentous E. coli templates and the use of S-layer proteins in a new material construct.
大肠杆菌是研究最为透彻的微生物之一，在异源生产其他生物体中具有特殊用途的有趣蛋白质的工具方面有多种应用。特殊表面 (S-) 层蛋白的异源表达导致大肠杆菌细胞形成非常长的细胞，当它们分裂成单个大肠杆菌细胞时，会留下透明的管。这些天然结构作为生物模板，对于开发用于多种应用的生物-无机复合材料具有很高的价值。在这项研究中，我们使用基因修饰的丝状大肠杆菌细胞作为模板，设计可以用作功能分子或颗粒载体的聚电解质管。生物材料结构的多样性有可能被用于构建反映生物模板形式的无机或聚合高级杂化材料。这种受生物启发的材料在生物学、化学和材料科学等多个科学领域都具有很大的兴趣，并可用于构建功能性材料或受生物启发的无机纳米颗粒合成。
将基因修饰的丝状大肠杆菌细胞固定在 2%戊二醛中，并涂覆交替的六聚体聚阴离子聚电解质聚（对苯乙烯磺酸钠）（PSS）和聚阳离子聚电解质聚（盐酸烯丙胺）（PAH）。之后，我们用 1.2%次氯酸钠溶解大肠杆菌细胞，从而获得直径为 0.7μm、长度为 5-50μm 的中空聚电解质管。为了功能化，将聚电解质管涂覆 S-层蛋白聚合物，然后用 Pd(0)颗粒进行金属化。使用光学显微镜、扫描电子显微镜、能量色散 X 射线光谱和透射电子显微镜对这些组件进行了分析。
这种新材料的构建为各种应用提供了可能性，例如新型催化剂或用于电子设备的金属纳米线。这项工作的新颖之处在于使用丝状大肠杆菌模板和在新材料构建中使用 S-层蛋白。
