On the Interactions of Proteins with Silicon-Based Materials
In this chapter we describe silica precipitation using unmodified synthetic R5 polypeptide—a nineteen amino acid sequence corresponding to the homologous repeating sequence in silaffin-1A protein extracted from diatom C. fusiformis. The particle formation was investigated using modern materials characterization methods, namely AFM, SEM and EDS. It was found that silica particles of sizes ∼150–200 nm were produced and that they formed aggregates. Furthermore, we propose that the R5 polypeptide self-organizes in solution and catalyzes and scaffolds the silica formation in vitro. We believe that silaffin proteins and other proteins facilitating silica formation in vivo behave in a similar fashion and this may provide insights into the role of proteins in biosilicification.
KeywordsBiomineralization Biosilicification Biosilica Proteins Silicatein Silaffin-1A catalysis of silica particles formation
We thank Dr. Srinivas Subramaniam (CME, UC) for help with the SEM analysis. The financial support for the work described in this chapter was kindly provided by DAGSI.
- 3.Round FE, Crawford RM, Mann DG (1990) The diatoms, biology and morphology of the genera. Cambridge University Press, Cambridge Google Scholar
- 8.Kröger N, Bergsdorf C, Sumper M (1994) A new calcium-binding glycoprotein family constitutes a major diatom cell-wall component. EMBO J 13:4676–4683 Google Scholar
- 13.Clarson SJ, Whitlock PW, Patwardhan SV, Brott LL, Naik RR, Stone MO (2002) Synthesis of silica nanostructures at neutral pH using catalytic polypeptides. Polym Mater Sci Eng 86:81 Google Scholar
- 17.Iler RK (1979) The chemistry of silica: solubility, polymerization, colloid and surface properties and biochemistry. Wiley, New York, Chap 3 Google Scholar
- 21.Sullivan BE (1986) In: Silicon biochemistry. Wiley, Chichester, Chap 5 Google Scholar
- 25.Patwardhan SV, Durstock MF, Clarson SJ (2002) Silicification and biosilicification: Part 2. Silicification at pH 7 in the presence of a cationically charged polymer in solution and immobilized on substrates. In: Synthesis and Properties of Silicones and Silicone-Modified Materials. ACS Symposium Series, Vol 838, pp 366–374 CrossRefGoogle Scholar
- 27.Patwardhan SV, Clarson SJ (2003) Silicification and biosilicification: Part 5. An investigation of the silica structures formed at weakly acidic pH and neutral pH as facilitated by cationically charged macromolecules. Mater Sci Eng C 23:495–499 Google Scholar