Experimental characterization of proteins immobilized on Si-based materials

We studied the possibility to use techniques that are traditionally employed in microelectronics to detect biological molecules immobilized on and into Si-based materials having, as final goal, the structural characterization of a glucose biosensor. The inorganic immobilization surfaces used were both bulk and porous silicon dioxide and the biological molecule to monitor was the enzyme glucose oxidase, widely used as a sensing element in glucose biosensors. Bulk SiO2 was used to optimize the immobilization protocol and the step-by-step characterization was mainly carried out by Atomic Force Microscopy measurements. Once optimized, the same protocol was used to anchor the enzyme in a porous Si dioxide matrix. Traditional measurement techniques may fail in biological molecule detection since C, basic element of such biological molecules, is present in Si as a contaminant, or introduced during sample preparation, e.g. for TEM cross section analysis. The enzyme monitoring was carried out by electron diffraction X-ray measurements coupled with scanning electron microscopy and to be sure of the protein presence, it was previously labelled with gold nano particles. We believe that this la