Macromolecular Chemistry

Phosphoregulation during morphogenesis in diatoms

Diatoms are a large and diverse group of unicellular eukaryotic algae. They are crucial components of marine ecosystems, and play an important role in biogeochemical cycles of carbon, nitrogen, phosphor, silicon and iron. Another important feature is the biomineralised cell wall consisting of structured silica particles in the range of a few nanometer up to several microns. The cell wall represents a model for photonic crystal slabs and may be useful in physical applications. [Fuhrmann et al., 2004]

The analysis of organic molecules playing a crucial role in biosilicate formation showed that zwitterionic silaffins (post-translationally encoded proteins), long-chain polyamines and acidic silacidins are involved. Sumper and coworkers demonstrated the influence of silaffins and polyamines in the preparation of silicate precipitates from monosilic acid solutions to form spherical SiO2 networks. The diameter of this spherical structures is affected by the reaction conditions, such as the pH value or the molarity of the reagents used. [Sumper, 2011] However, the presence of multivalent anions such as phosphate or phosphorylated proteins (silaffins) is required. The investigation of phosphorylation thus allows insight and access to a biomimetic design of nanostructured patterns.

In our lab, we are interested in understanding this biomineralisation from a physical-chemical standpoint by combining different methods.

References:
 
Sumper, M. (2011) Biomimetic patterning of silica by long-chain polyamines. Angew. Chem. Int. Ed. 2004, 43, 2251 –2254
Fuhrmann, T., Landwehr, S., El Rharbi-Kucki, M., Sumper, M. (2004) Diatoms as living photonic crystals. Appl. Phys.B 78, 257– 260