"This interdisciplinary proposal will investigate whether the activity of a unique family of membrane transport proteins can be harnessed to develop novel strategies for the bioinspired fabrication of nanoscale materials and provide new directions in synthetic biology. Silicon transporters (SITs) are integral membrane proteins that were first identified in the diatoms, single–celled eukaryotic algae that surround themselves with a cell wall of hydrated silica. The biosynthesis of this ‘glass house’ depends upon the uptake of silicic acid, the soluble form of silica, from the environment. The SITs bind silicic acid with high affinity and transport it across the cytoplasmic membrane into the cell. Under this proposal the SITs will be recombinantly expressed and purified before being reconstituted into synthetic liposomes. The resulting proteoliposomes will be energized to drive SIT-dependent transport of silicic acid into the interior lumen. Since the lumen has dimensions on the nanometer length scale and attolitre volume, the proteoliposomes will act as discrete nanoreactors for the synthesis of silica nanoparticles. Using SIT proteins to deliver silicic acid to the growing nanoparticle offers an unprecedented degree of tunable kinetic control over the synthetic conditions that, together with the lumen microenvironment, may induce novel particle morphologies or properties. This principle will be extended in two further directions. First, encapsulating preformed inorganic nanoparticles in the liposome lumen will lead to the formation of core-shell nanoparticles with a functional core and passive silica shell. Using SITs to control the supply of the synthetic precursor will provide unparalleled tight control over the thickness of the silica shell. A second element will create a diatom protocell by incorporating silica-condensing peptides into the lumen in order to generate silica nanostructures. This will establish a unique new methodology for nanoscale synthesis."