Materials synthesis in vivo – intracellular formation of nanostructured silica by microalgae

ended

Organisms evolved the ability to form a magnificent array of functional materials, which surpass any man-made product. A prominent example is diatoms, marine microalgae that form an intricate cell-wall made of meso-porous silica. Diatom silica is a tough, hierarchically built, and biocompatible material that is environmentally friendly and cheap, making it an exciting target for nanotechnology. Nevertheless, the principles of this regulated formation mechanism remain elusive. A persistent obstacle for elucidating biomineralization processes is the inaccessibility of the cellular environment for structural and chemical investigations. Recently, far-reaching developments in electron microscopy have revolutionized our abilities to investigate chemical processes inside living organisms. It is now becoming feasible to image and analyze, with nanometer-scale resolution, an intracellular mineralization process. This proposal aims to elucidate the intracellular mechanism of silica formation by diatoms. We will study cells undergoing the silicification process in situ, using a suite of state-of-the-art electron and X-ray imaging and spectroscopy tools. The combination of structural and chemical data will enable us to elucidate: 1) The concentration and stabilization mechanism of transient Si phases in the cell. 2) The nanoscale environment in which silica condensation takes place. 3) Genetic and environmental strategies to engineer the silicification process for designed outcomes. Diatom silica is a promising material for applications such as photonics, pharmaceuticals, and catalysis, which require hierarchical, high-surface area, nano-materials. The achievements of this project will inspire synthetic methodologies to produce and design nano-patterned silica, and genetically-engineer the biological silicification process to produce custom-made materials.