Potentiometric Detection of Single Nucleotide Polymorphism by Using a Genetic Field‐effect transistor

Abstract

Potentiometric measurement of allele-specific oligonucleotide hybridization based on the principle of detection of charge-density change at the surface of a gate insulator by using of a genetic field-effect transistor has been demonstrated. Since DNA molecules are negatively charged in aqueous solution, a hybridization event at the gate surface leads to a charge-density change in the channel of the FET and can be directly transduced into an electrical signal without any labeling of target DNA molecules. One of the unique features of our method is to utilize DNA binders such as intercalators as charged species for double-stranded DNA after hybridization, since these are ionized and carry positive charges in aqueous solution. Single-base mismatch of the target DNA could be successfully detected both with the wild-type and with the mutant genetic FETs by controlling the hybridization temperatures and introducing Hoechst 33258 as DNA binder. The genetic FET platform is suitable as a simple, accurate, and inexpensive system for SNP typing in clinical diagnostics.

Development of cell/transistor interface for real-time and noninvasive monitoring of potassium ion release based on apoptosis using biologically-coupled field effect transistor

“…Thus, the variation of K + concentration was successfully detected using the prepared FET. The charge density change at the gate insulator could be detected as a shift of potential difference of the prepared FET, so the number of crown ether per unit area related to the shift of potential difference per decade of K + concentration ( V) can be estimated [11].…”

Electronic Detection of Biomarkers by Si Field-Effect Transistor from Undiluted Sample Solutions with High Ionic Strengths

“…First, APTES self-assembly monolayer (SAM) was formed on a 2 × 2 cm 2 bulk Si substrate via a silanization reaction. 7,[10][11][12][13][14][15][16][17] Immediately thereafter, the APTES-immobilized Si substrate was immersed in a 25 wt % glutaraldehyde solution containing 4 mM NaBH 3 CN (pH 8.4) for 4 h for the formation of aldehyde functional groups (-CHO) on the silicon channels. Finally, the chip functionalized with the aldehyde group was immersed in a 250 µg/mL solution of mab-PSA antibody (4 mM NaBH3CN, pH 8.4) overnight, and the sensor was then immersed in a 1% BSA solution (4 mM NaBH3CN, pH 8.4) for approximately 1 h to block aldehyde functional groups that did not react with the mab-PSA.…”

Real-time label-free quantitative monitoring of biomolecules without surface binding by floating-gate complementary metal-oxide semiconductor sensor array integrated with readout circuitry

“…These sensors can be easily miniaturized at low cost using standard integrated circuit fabrication processes and provide the capability of monolithic integration with readout circuitry to enhance the signal-to-noise ratio. 6,7 However, in order to detect DNA molecules, it is required to immobilize single-stranded probes on the surface of the ion-sensitive devices for the hybridization of single-stranded complementary target molecules in the electrolyte solution [8][9][10] or to deposit a positively charged layer such as poly-L-lysine on the sensing electrodes to attract the negatively charged nucleic acid molecules. 11,12 These additional processes increase reaction time and the complexity in detection protocols.…”