Immobilizzation of Glucose oxidase in silicon dioxide: chemical-fisical, electric and enzymatic characterization

The recognition abilities of biological molecules and their specificity are object of increasing interest by the scientific community, also for their potential use in biosensors fully integrated in microelectronic chips. Aim of this work was the optimization of an immobilization protocol of biomolecules on silicon dioxide (SiO2) surfaces to build a biosensor, which has electrical transducer. We chose to use the Glucose oxidase (GOx) protein as bioreceptor and a SiO2 layer as immobilization surface, which is possible to integrate into a microelectronic device. To test the protocol validity and the uniformity of the organic layer obtained, we used X-ray Photoelectron Spectroscopy (XPS) [1]. In particular, we demonstrated the enzyme presence monitoring both the C1s and N1s signals; while the XPS Si2p signal, monitored during the various immobilization steps, allowed us to verify the layer uniformity. We demonstrated that the glucose oxidase activity was maintained after immobilization by using spectrophotometric measurements. Finally, to demonstrate that is possible use electrical transduction, we carried out the electrical characterization of biological molecules immobilized on the dielectric of a MOSlike structure.