▎ 摘　　要

NOVELTY - Nucleic acid detection device comprises a graphene chip that comprises a substrate, a graphene surface on the substrate, a conducting substance at two ends of the graphene surface to form a first electrode and a second electrode, and an insulating substance to insulate the first electrode and the second electrode; a double-stranded nucleic acid probe attached to the graphene surface of the reservoir; and a microcontroller board that comprises a digital meter to measure electric current that passes through the graphene chip when an input voltage is applied to the graphene chip. USE - The nucleic acid detection device is useful for detecting or discriminating nucleic acid having one or more mismatches (claimed), where the nucleic acids are specific nucleic acid molecules for diagnosing diseases such as cancer or genetic diseases, forensics, or for preparing personalized medicines. ADVANTAGE - Provided are nano-sensors and techniques for their design, engineering, and use for detection and discrimination of nucleic acids with a high resolution, sensitivity or specificity. The nano-sensors have achieved about 200000-fold enhancement of sensitivity for detection of nucleic acid molecules compared to current nano-devices. DETAILED DESCRIPTION - Nucleic acid detection device comprises a graphene chip that comprises a substrate, a graphene surface on the substrate, a conducting substance at two ends of the graphene surface to form a first electrode and a second electrode, and an insulating substance to insulate the first electrode and the second electrode, where the insulating substance further forms a solution reservoir on the graphene surface to receive a nucleic acid probe and a sample nucleic acid; a double-stranded nucleic acid probe attached to the graphene surface of the reservoir, where the nucleic acid probe comprises a normal strand having a toehold at one end and a weak strand comprising one or more inosines substituting guanines; and a microcontroller board that comprises a digital meter to measure electric current that passes through the graphene chip when an input voltage is applied to the graphene chip, and a communication module to send values of the measured electric current and the input voltage. An INDEPENDENT CLAIM is a method of detecting or discriminating a nucleic acid having one or more mismatches, comprising contacting a double-stranded nucleic acid probe in a solution reservoir on a graphene chip such that the nucleic acid probe is attached to the surface of the graphene chip; contacting a control nucleic acid that is completely complementary to the probe with the probe nucleic acid attached to the graphene surface such that strand displacement occurs between the probe nucleic acid and the control nucleic acid; measuring the electric signal changes during the strand displacement between the probe nucleic acid and the control nucleic acid to obtain a first I-V curve; contacting a target nucleic acid that is partially complementary to the probe with the probe attached to the graphene surface such that strand displacement occurs between the probe nucleic acid and the target nucleic acid; measuring the electric signal changes during the strand displacement between the probe nucleic acid and the target nucleic acid to obtain a second I-V curve; and comparing the second I-V curve with the first I-V curve, where a shift in the curve indicating the presence of one or more mismatches in the target nucleic acid; or a method of detecting or discriminating a nucleic acid having one or more mismatches, comprising contacting a double-stranded probe nucleic acid with a control nucleic acid that is fully complementary to the probe such that a strand displacement between the probe nucleic acid and the control nucleic acid occurs; measuring the kinetics of strand displacement of the probe and the control nucleic acid; contacting the probe nucleic acid with a target nucleic acid having one or more mismatches with the probe such that a strand displacement between the probe nucleic acid and the target nucleic acid occurs; measuring the kinetics of strand displacement of the probe and the target nucleic acid; and comparing the kinetics of the strand displacement of the target nucleic acid with the kinetics of the strand displacement of the control nucleic acid, where a change in the kinetics indicating the presence of one or more mismatches in the target nucleic acid.