Light emitting silica nanostructures by surface functionalization of diatom algae shells with a triethoxysilane-functionalized π-conjugated fluorophore

The functionalization of biosilica shells (frustules) of diatoms microalgae with a tailored luminescent molecule is a convenient, scalable and biotechnological approach for obtaining new light emitting silica nanostructures with promising applications in photonics. In particular, here we report the synthesis of a red emitting organic fluorophore and its covalent linking to the surface of mesoporous biosilica extracted from Thalassiosira weissflogii diatoms cultured in our laboratories. The organic dye has a conjugated skeleton composed of thienyl, benzothiadiazolyl and phenyl units and a peripheral triethoxysilyl group which enables its stable binding onto the frustules surface. The protocol to extract the biosilica shells from living diatoms preserving their natural ornate nanostructured morphology is also discussed.