Gene detection field-effect device and method of analyzing gene polymorphism therewith

A method of analyzing gene polymorphism using

• a first, second, and third gene detection field-effect device,
• wherein each of said first and second gene detection field-effect device is provided with an insulation film including a nucleic acid probe immobilized on one of the surfaces thereof, a semiconductor substrate being installed so as to abut against the other surface of the insulation film, and a reference electrode, and
• wherein said third gene detection field-effect device is provided with an insulation film free of a nucleic acid probe immobilized on one of the surfaces thereof, a semiconductor being installed so as to abut against the other surface of the insulation film, and a reference electrode;
• the method comprising the steps of:
• (a) bringing a wild-type nucleic acid probe immobilized to the insulation film of the first gene detection field-effect device into contact with sample solution containing at least one target gene to hybridize the nucleic acid probe and the target gene on the insulation film,
• bringing a mutant-type nucleic acid probe immobilized to the insulation film of the second gene detection field-effect device into contact with sample solution containing the at least one target gene to hybridize the nucleic acid probe and the target gene on the insulation film, and
• bringing the insulation film free of nucleic acid probe immobilized thereon of the third gene detection field-effect device into contact with sample solution containing the at least one target gene to hybridize the nucleic acid probe and the target gene on the insulation film;
• (b) introducing cleaning liquid on the respective insulation films of the first, second, and third gene detection field-effect devices to remove the target gene which is not reacted;
• (c) introducing deoxyadenosine triphosphoric acid (dATP), deoxyguanosine triphosphate (dGTP), deoxycytidine triphosphate (dCTP), and deoxythymidine triphosphate (dTTP) as ground substances onto the respective insulation films of the first, second, and third gene detection field-effect devices along with Taq DNA polymerase as an enzyme for elongation to cause elongation;
• (d) introducing cleaning liquid on the respective insulation films of the first, second, and third gene detection field-effect devices to remove the enzyme and the ground substances which are not reacted;
• and
• (e) introducing buffer liquid on the respective insulation films of the first, second, and third gene detection field-effect devices, and measuring a differential output value V1 between the first gene detection field-effect device and the third gene detection field-effect device;
• measuring a differential output value V2 between the second gene detection field-effect device and the third gene detection field-effect device, and classifying into three patterns;
• a pattern in which V1 is larger than (V2(V1>V2), a pattern in which V1 and V2 is almost the same (V1≈V2), and a pattern in which V1 is smaller than V2 (V1<V2) and displaying the same;
• and measuring an output value of the gene detection field-effect device.