An apparatus and method for the detection of localized variations in ionic charge in a chemical reaction by means of ion-sensitive field effect transistors

摘要

Sensor and method to detect localised fluctuations of ionic charge indicating events occuring during a chemical reaction, the sensing apparatus comprising an ion sensitive field effect transistor (ISFET) arranged to generate an electrical output signal in response to localised fluctuations of ionic charge at or adjacent the surface of the transistor, and means for detecting the electrical output signal from the field effect transistor is provided with a polymerase linked layer and the chemical reaction is DNA synthesis, and the localised fluctuations of ionic charge indicate the insertion of di-deoxynucleotide triphosphates (ddNTP) and deoxynucleotide triphosphates (dNTP) by detecting a change of hydronium ions (pH value) with a sensitive Si 3 N 4 layer of the field effect transistor. The method is a modification to Sanger sequencing where the final stage of electrophoretic separation and subsequent detection of nucleotides is replaced by measurements of the pH by the ISFET.