Functionalization of Si/SiO2 substrates with homooligonucleotides for a DNA biosensor

Si/SiO2 substrates bearing single stranded homooligonucleotidic sequences a re implemented, in order to use as DNA biosensors based on field effect mea surement. The oligonucleotides are immobilized on the substrates by two dif ferent methods, with either an aminosilane or a glycidoxysilane. We present investigations and characterizations of both methods of immobilization, us ing radiolabelling and electrochemical impedance measurements on electrolyt e/dielectric/semiconductor heterostructures. In our conditions of reaction, the protocol using glycidoxysilane allows a denser and more robust immobil ization of oligonucleotides than with the aminosilane. (C) 1999 Elsevier Sc ience S.A. All rights reserved.