Biotemplate und Phagen Display

Phage Display

Fig. 1: Phage Display.
A) A randomized peptide library
expressed on the surface of M13 phages is incubated
with the target substrate.
B) Non-bound peptide-phages complexes are eliminated.
C) Specifically binding phages are eluted
and the peptide sequence is determined.
Fig. 2:  Application fields of inorganic-binding peptides.

The synthesis of inorganic materials (e.g. oxide ceramics) can be controlled by peptides. For the identification of specific inorganic-binding peptides the phage display method is applied (Fig. 1). There, a peptide library is expressed on the surface of genetically modified M13 phages. The peptide library is incubated with the target substrate (substrate of interest) and the specific interacting peptides bind the peptide-phage complex to the target material. Peptide-phage complexes expressing non-interacting peptides are eliminated. Finally, the peptide-phage complexes expressing specifically binding peptides are eluted from the target substrate. The peptide sequence is determined by sequencing the corresponding peptide-coding DNA sequence. The binding amino acid residues of the inorganic-binding peptides are determined by NMR measurements. In addition, the affinity (KD) of the peptide to the substrate can be determined by NMR, surface plasmon resonance (SPR), or quartz crystal microbalance (QCM). The binding strength of peptide-phage complexes are determined by a binding assay. The identified peptides is used for various applications in the field of material synthesis (Fig. 2.). Peptides are applied in mineralization reactions to control the morphology and polymorph of minerals (cf. Bioinspired mineralization). Expressed on the surface of biotemplates (e.g. M13 phages, tobacco mosaic virus) the peptides influence the mineralization of the template. This allows the generation of technically interesting 2D and 3D organic-inorganic hybridmaterials in the nanometer range.

 

Biotemplate:

Fig. 3: Tobacco mosaic virus (TMV) as biotemplate for the ZnO mineralization.

There are many examples of evolutionary optimized organic-inorganic hybridmaterials in nature revealing extraordinary material properties. Such materials, like nacre, are mineralized in the presence of biomolecules which function as a complex template for the deposition of inorganic material or as a structure directing agent. Inspired by this natural process, we developed synthesis reactions for the generation of technologically relevant materials like zinc oxide (ZnO) under moderate reaction conditions (e.g. temperature, pressure, pH) in the presence of a bio-template. Various bio-templates like DNA, phages or viruses have been applied. The tobacco mosaic virus (TMV) is a rod shaped 300 nm long virus with a diameter of 18 nm harboring an inner channel of 4 nm in diameter. TMV is applied as template for the deposition of ZnO in chemical bath deposition (CBD) reactions where the virus shape is exactly maintained (Fig. 3 and 4). Furthermore, the genetic modification of the coat proteins (surface expressed proteins) opens a wide field to control the interaction of the organic template and the inorganic material.

Fig. 4: Cross section of a TMV/ZnO nano wire
(HRTEM image).

TMV/ZnO hybridmaterials were successfully applied for the generation of a field effect transistor (FET). The TMV based FET can be directly used without the usual post-treatment (e.g. heat, radiation). The FETs show a good saturation behavior and only a small hysteresis.

 



Projects

DFG PAK 410: Biologische Erzeugung von Oxidkeramiken http://www.bionik.uni-stuttgart.de
BI469/15-1
In vitro und in vivo Synthesen von Oxidkeramiken

DFG RO3965/1-1
Identifikation undCharakterisierung con Zirkoniumdioxid-affinen Peptiden zur Mineralisation von Zirkoniumdioxid

SPP 1569: Generation of multifunctional inorganic materials by molecular bionics
http://www.uni-stuttgart.de/spp1569/index.html

BI469/19-1
Genetically optimized Tobacco mosaic viruses as scaffold for the in vitro generation of semiconductor bio/metal oxide nanostructured architectures
http://www.uni-stuttgart.de/spp1569/projects/genetically_optimzed.html

Literature

Rothenstein, D., Claasen, B., Omiecienski, B., Lammel, P., Bill, J., 2012. Isolation of ZnO-Binding 12-mer Peptides and Determination of Their Binding Epitopes by NMR Spectroscopy. Journal of the American Chemical Society 134, 12547-12556.

Atanasova, P., Rothenstein, D., Schneider, J.J., Hoffmann, R.C., Dilfer, S., Eiben, S., Wege, C., Jeske, H., Bill, J., 2011. Virus-Templated Synthesis of ZnO Nanostructures and Formation of Field-Effect Transistors. Advanced Materials 23, 4918-4922.

Atanasova, P., Weitz, R.T., Gerstel, P., Srot, V., Kopold, P., van Aken, P.A., Burghard, M., Bill, J., 2009. DNA-templated synthesis of ZnO thin layers and nanowires. Nanotechnology 20, 365302.