S-layer templated bioinspired synthesis of silica.
The current understanding of the molecular mechanisms involved in the bioinspired formation of silica structures laid foundation for investigating the potential of the S-layer protein SbpA from Lysinibacillus sphaericus CCM 2177 as catalyst, template and scaffold for the generation of novel silica architectures. SbpA reassembles into monomolecular lattices with square (p4) lattice symmetry and a lattice constant of 13.1 nm. Silica layers on the S-layer lattice were formed using tetramethoxysilane (TMOS) and visualized by transmission electron microscopy. In situ quartz crystal microbalance with dissipation monitoring (QCM-D) measurements showed the adsorption of silica in dependence on the presence of phosphate in the silicate solution and on the preceding chemical modification of the S-layer. An increased amount of precipitated silica could be observed when K2HPO4/KH2PO4 was present in the solution (pH 7.2). Further on, independent of the presence of phosphate the silica deposition was higher on S-layer lattices upon activation of their carboxyl groups with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) compared to native S-layers or EDC treated S-layers when the activated carboxyl groups were blocked with ethylene diamine (EDA). Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy revealed the formation of an amorphous silica gel (SiO2)x.yH2O on the S-layer. The silica surface concentrations on the S-layer was 4 x 10(-9) to 2 x 10(-8) mol cm(-2) depending on the modification of the protein layer and corresponded to 4-21 monolayers of SiO2.
Center for NanoBiotechnology, University of Natural Resources and Applied Life Sciences, Vienna, Gregor-Mendel-Strasse 33, A-1180 Vienna, Austria.
Caren
C
Göbel
Bernhard
B
Schuster
Dieter
D
Baurecht
Uwe B
UB
Sleytr
Dietmar
D
Pum
D000327:Adsorption; D001426:Bacterial Proteins / Q000378:metabolism*; D003460:Crystallization; D005022:Ethyldimethylaminopropyl Carbodiimide / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D008956:Models, Chemical; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D055550:Protein Stability; D011791:Quartz / Q000737:chemistry; D012822:Silicon Dioxide / Q000138:chemical synthesis* / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014783:Viscosity
D001426:Bacterial Proteins; D009004:Monosaccharide Transport Proteins; C120455:SbpA protein, bacteria; D011791:Quartz; D012822:Silicon Dioxide; D005022:Ethyldimethylaminopropyl Carbodiimide