Nanostructured sol-gel composites for electroanalysis

The sol-gel technique provides a versatile way for the fabrication of inorganic, bio-inorganic and inorganic-organic hybrid materials, that are relatively easy to prepare under mild conditions, and with a variety of controlled product properties, such as functionality, rigidity, porosity, connectivity and hydrophobicity. Using a functional precursor, bis[3-(triethoxysilyl)propyl]tetrasulfide (SIS), we have prepared various nanostructured sol-gel composites for electroanalytical applications: (a) Molecularly-imprinted sol-gel films. Two types of pore channels constructed by templated cavities of different size and shape showed high discrimination for molecular recognition. (b) Chemically derived Prussian blue sol-gel composite films. Applications in the development of a potassium ion-selective electrodes. (c) Electrocrystallized platinum sol-gel nanocomposites. Laterally dendritic platinum aggregations from 3 to 5 nm primary particles were electrodeposited on sol-gel modified carbon surfaces, holding great promise for Pt-catalyzed reactions. (d) Site-directed immobilization of biomolecules on functionalized sol-gel films. The immobilized enzymes showed high activity and stability.