Deoxyribonucleic acid measuring apparatus and method of measuring deoxyribonucleic acid

摘要

With an insulated gate field effect transistor in which deoxyribonucleic acid (DNA) probes are immobilized on a gold electrode, extension reaction on the gold electrode is performed with DNA polymerase to directly measure an increased amount of a phosphate group caused by the extension reaction, that is, negative charge, by means of a current change between a source and a drain of the insulated gate field effect transistor. Thus, presence/absence of hybridization of target DNAs with the DNA probes, and presence/absence of the extension reaction are detected. Optimum immobilization density of the DNA probes on the gold electrode is set at 4x10¹² molecules/cm². To reduce surface potential fluctuation caused by external variation (influences of foreign substances), which is a problem when using the gold electrode in a solution, a high-frequency voltage equal to or above 1 kHz is applied between the gold electrode and a reference electrode by a power source.