Method for determination of DNA and sensor therefor.

摘要

This invention, for the purpose of eliminating such drawbacks of the conventional DNA test as a complicate and time-consuming operation due to inevitable use of isotope, provides a DNA sensor which comprises a mass detecting element of ultrahigh sensitivity composed of quartz oscillation electrodes and an immobilizing chemical species (modifying substance) attached to one terminal of a DNA whose other terminal is immobilized to the surface of the element. This DNA sensor enjoys high sensitivity by harnessing the outstanding selectivity of complementary bondage of DNA and the action of chemical amplification of mass variation. The DNA sensor of this invention is enabled to attain the DNA detection on the order of one DNA by setting the detection limit of the element used as the substrate at a level smaller than the mass of the modifying substance. It is characterized by obtaining a multiple of the mass of the modifying substance in the form of digital response. Even when the detection limit inherent in the element is larger than the mass of the immobilized chemical species, the DNA detection by this method allows the variation of mass to be measured in an amplified form and operates in the direction of decreasing the variation of mass. Contrary to such actions as adsorption of a nonspecific chemical species, the operation of this DNA sensor suffers only inconspicuously from the largeness of detection limit and permits accurate determination.