Immobilization of oligonucleotide probes on Si 3N 4 surface and its application to genetic field effect transistor

Abstract

We have been developing a genetic field effect transistor (FET) which is based on potentiometric detection of allele-specific oligonucleotide hybridization on the Si 3N 4 gate insulator. In this study, the surface characteristics of DNA-immobilized Si 3N 4 film were investigated using time-of-flight secondary ion mass spectrometry (TOF-SIMS) and a genetic field effect transistor. The immobilization of oligonucleotide probes on the Si 3N 4 surface was analyzed by the mass spectra and the electrical potential signals. By the use of the genetic field effect transistor, the immobilization density of oligonucleotide probes on the Si 3N 4 gate insulator was calculated as 1.7×10 8/cm 2 from the threshold voltage shift and was considered to influence the sensitivity of DNA hybridization detection.