title: Electrical detection of biomolecular interactions with metal-insulator-semiconductor diodes.
abstract: We report the label-free detection of DNA hybridization using a metal-insulator-semiconductor (MIS) diode or capacitor. Upon immobilization of single-stranded DNA on the gold gate of a MIS capacitor, the capacitance versus voltage characteristics show a significant shift in the direction of negative voltages as expected from the immobilization of negative charges on the gate. The hybridization with the complementary strand gives rise to a further significant shift in the same direction as before, which is consistent with the increase of negative charges on the gate brought about by the hybridization. Fluorescence studies indicate that the immobilization and hybridization of DNA can be electrostatically promoted by electric fields externally applied to the MIS capacitors. The MIS diode detection method is applicable to all biomolecular interactions that affect the surface dipole at the interface between the metal gate and the electrolyte and can be extended to other chemical and biochemical systems such as proteins and cells.
authors.affiliation: Engineering Department, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK. pme22@cam.ac.uk
authors.forename: P
authors.initials: P
authors.lastname: Estrela
authors.forename: P
authors.initials: P
authors.lastname: Migliorato
authors.forename: H
authors.initials: H
authors.lastname: Takiguchi
authors.forename: H
authors.initials: H
authors.lastname: Fukushima
authors.forename: S
authors.initials: S
authors.lastname: Nebashi
mesh_terms: D000327:Adsorption; D001704:Biopolymers / Q000032:analysis / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D004247:DNA / Q000032:analysis* / Q000737:chemistry* / Q000235:genetics; D004553:Electric Conductivity; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017403:In Situ Hybridization / Q000295:instrumentation* / Q000379:methods; D008670:Metals / Q000737:chemistry; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012666:Semiconductors; D012680:Sensitivity and Specificity
chemical_list: D001704:Biopolymers; D020099:Coated Materials, Biocompatible; D008670:Metals; D004247:DNA