Ultrasensitive detection of Hg2+ using oligonucleotide-functionalized AlGaN/GaN high electron mobility transistor

An oligonucleotide-functionalized ion sensitive AlGaN/GaN high electron mobility transistor (HEMT) was fabricated to detect trace amounts of Hg2+. The advantages of ion sensitive AlGaN/GaN HEMT and highly specific binding interaction between Hg2+ and thymines were combined. The current response of this Hg2+ ultrasensitive transistor was characterized. The current increased due to the accumulation of Hg2+ ions on the surface by the highly specific thymine-Hg2+-thymine recognition. The dynamic linear range for Hg2+ detection has been determined in the concentrations from 10(-14) to 10(-8) M and a detection limit below 10(-14) M level was estimated, which is the best result of AlGaN/GaN HEMT biosensors for Hg2+ detection till now. (C) 2014 AIP Publishing LLC.