Electrical detection of deoxyribonucleic acid hybridization with AlGaN/GaN high electron mobility transistors

Au-gated AlGaN/GaN high electron mobility transistor (HEMT) structures were functionalized in the gate region with label-free 3(')-thiol-modified oligonucleotides. This serves as a binding layer to the AlGaN surface for hybridization of matched target deoxyribonucleic acid (DNA). X-ray photoelectron spectroscopy shows the immobilization of thiol-modified DNA covalently bonded with gold on the gated region. Hybridization between probe DNA and matched or mismatched target DNA on the Au-gated HEMT was detected by electrical measurements. The HEMT drain-source current showed a clear decrease of 115 mu A as this matched target DNA was introduced to the probe DNA on the surface, showing the promise of the DNA sequence detection approach for biological sensing. (c) 2006 American Institute of Physics.