Sensors using high electron mobility transistors

Abstract

Embodiments of the invention include sensors comprising high electron mobility transistors (HEMTs) with capture reagents on a gate region of the HEMTs. Example sensors include HEMTs with a thin gold layer on the gate region and bound antibodies; a thin gold layer on the gate region and chelating agents; a non-native gate dielectric on the gate region; and nanorods of a non-native dielectric with an immobilized enzyme on the gate region. Embodiments including antibodies or enzymes can have the antibodies or enzymes bound to the Au-gate via a binding group. Other embodiments of the invention are methods of using the sensors for detecting breast cancer, prostate cancer, kidney injury, glucose, metals or pH where a signal is generated by the HEMT when a solution is contacted with the sensor. The solution can be blood, saliva, urine, breath condensate, or any solution suspected of containing any specific analyte for the sensor.

1 . An AlGaN/GaN high electron mobility transistor (HEMT) based sensor for one or more target molecules in a sample, the sensor comprising:
 an AlGaN/GaN high electron mobility transistor (HEMT); and   at least one capture reagent on a gate region of the AlGaN/GaN HEMT.   
   
   
       2 . The sensor of  claim 1 , further comprising at least one wireless communication circuit on a chip, wherein the AlGaN/GaN HEMT comprises an array of HEMTs on the chip, and wherein a signal from the sensor is wirelessly transmittable. 
   
   
       3 . The sensor of  claim 1 , wherein the AlGaN/GaN HEMT comprises an Au-comprising gate, and wherein the capture reagent binds or otherwise associates with a breast cancer antigen. 
   
   
       4 . The sensor of  claim 3 , wherein the capture reagent is an antibody to a breast cancer antigen selected from EGF, c-erbB-2, CA15-3, and any combination thereof. 
   
   
       5 . The sensor of  claim 3 , further comprising a binding group layer to couple the capture reagent to the Au-comprising gate. 
   
   
       6 . The sensor of  claim 3 , wherein the binding group layer comprises thioglycolic acid. 
   
   
       7 . The sensor of  claim 3 , further comprising a control HEMT connected to a source region of the AlGaN/GaN HEMT, wherein the control HEMT includes the Au-comprising gate and a protective layer covering the Au-comprising gate. 
   
   
       8 . The sensor of  claim 1 , wherein the AlGaN/GaN HEMT comprises an Au-comprising gate, the sensor comprising at least one chelating agent as a capture reagent. 
   
   
       9 . The sensor of  claim 8 , comprising at least one chelating agent selected from the group consisting of thioglycolic acid (HSCH 2 COOH), cysteamine (NH 2 CH 2 CH 2 SH), 1,2-ethanedithiol (HSCH 2 CH 2 SH), dimercaprol (BAL), diaminoethanetetraacetic acid (EDTA), 2,3-bis-sulfanylbutanedioic acid (DMSA), and 2,3-dimercapto-1-propanesulfonic acid (DMPS). 
   
   
       10 . The sensor of  claim 8 , further comprising a control HEMT connected to a source region of the AlGaN/GaN HEMT, wherein the control HEMT includes the Au-comprising gate and a protective layer covering the Au-comprising gate. 
   
   
       11 . The sensor of  claim 1 , comprising a gate dielectric as a capture reagent for detecting hydronium ion. 
   
   
       12 . The sensor of  claim 11 , wherein the gate dielectric comprises a non-native metal oxide. 
   
   
       13 . The sensor of  claim 12 , wherein the metal oxide comprises at least one of Sc 2 O 3 , Al 2 O 3 , TiO 2 , MgO, In 2 O 3 , SnO 2 , ZnO, and ZnMgO. 
   
   
       14 . The sensor of  claim 11 , further comprising a control HEMT connected to a source region of the AlGaN/GaN HEMT, wherein the control HEMT includes the gate dielectric and a protective layer covering the gate dielectric. 
   
   
       15 . The sensor of  claim 1 , wherein the AlGaN/GaN HEMT comprises an Au-comprising gate, and wherein the capture reagent comprises an antibody to kidney injury molecule-1 (KIM-1). 
   
   
       16 . The sensor of  claim 15 , further comprising a binding group layer to couple the antibody to the Au-comprising gate. 
   
   
       17 . The sensor of  claim 16 , wherein the binding group layer comprises thioglycolic acid. 
   
   
       18 . The sensor of  claim 15 , further comprising a control HEMT connected to a source region of the AlGaN/GaN HEMT, wherein the control HEMT includes the Au-comprising gate and a protective layer covering the Au-comprising gate. 
   
   
       19 . The sensor of  claim 1 , wherein the AlGaN/GaN HEMT comprises an Au-comprising gate, and wherein the capture reagent comprises a PSA antibody. 
   
   
       20 . The sensor of  claim 19 , further comprising a binding group layer to couple the PSA antibody to the Au-comprising gate. 
   
   
       21 . The sensor of  claim 20 , wherein the binding group layer comprises thioglycolic acid. 
   
   
       22 . The sensor of  claim 19 , further comprising a control HEMT connected to a source region of the AlGaN/GaN HEMT, wherein the control HEMT includes the Au-comprising gate and a protective layer covering the Au-comprising gate. 
   
   
       23 . The sensor of  claim 1 , comprising a gate dielectric layer comprising nanorods on the gate region, and glucose oxidase immobilized on the nanorods as the capture reagent. 
   
   
       24 . The sensor of  claim 23 , wherein the nanorods comprise a metal oxide. 
   
   
       25 . The sensor of  claim 24 , wherein the metal oxide comprises at least one of Sc 2 O 3 , Al 2 O 3 , TiO 2 , MgO, In 2 O 3 , SnO 2 , ZnO, and ZnMgO. 
   
   
       26 . The sensor of  claim 23 , further comprising a control HEMT connected to a source region of the at least one AlGaN/GaN HEMT, wherein the control HEMT includes the gate dielectric layer comprising the nanorods and a protective layer covering the Au-comprising gate. 
   
   
       27 . A method of detecting a target molecule in a sample comprising the steps of:
 providing a sample suspected of containing a target molecule; and   contacting the sample with a sensor comprising an AlGaN/GaN high electron mobility transistor (HEMT) and at least one capture reagent on a gate region of the AlGaN/GaN HEMT, wherein a signal is generated by the sensor when the target molecule is present in the sample and interacts with the capture reagent.   
   
   
       28 . The method of  claim 27 , wherein the sensor further comprises at least one wireless communication circuit on a chip, wherein the HEMT comprises an array of HEMTs on a chip, and wherein the signal is wirelessly transmittable. 
   
   
       29 . The method of  claim 28 , further comprising the step of transmitting wirelessly the signal to a receiver for the signal. 
   
   
       30 . The method of  claim 27 , wherein the sample is saliva, the target molecule is a breast cancer antigen, the HEMT comprises an Au-comprising gate, and the capture reagent is an antibody to the breast cancer antigen. 
   
   
       31 . The method of  claim 30 , wherein the sensor further comprises a binding agent layer to couple the antibody to the Au-comprising gate. 
   
   
       32 . The method of  claim 31 , wherein the binding group layer comprises thioglycolic acid. 
   
   
       33 . The method of  claim 27 , wherein the sample is aqueous, the target molecule is a metal, the HEMT comprises an Au-comprising gate, and the capture reagent comprises a chelating agent. 
   
   
       34 . The method of  claim 33 , wherein the metal is selected from the group consisting of Hg 2+ , Cu + 2, and Pb 2+  ion. 
   
   
       35 . The method of  claim 27 , wherein the sample is exhaled breath condensate, the target molecule is hydronium ion, and the HEMT comprises a gate dielectric that functions as a capture reagent. 
   
   
       36 . The sensor of  claim 35 , wherein the gate dielectric comprises a non-native metal oxide. 
   
   
       37 . The sensor of  claim 36 , wherein the non-native metal oxide comprises at least one of Sc 2 O 3 , Al 2 O 3 , TiO 2 , MgO, In 2 O 3 , SnO 2 , ZnO, and ZnMgO. 
   
   
       38 . The method of  claim 27 , wherein the sample is aqueous, the target molecule is kidney injury molecule-1(KIM-1), the HEMT comprises an Au-comprising gate, and the capture reagent comprises a KIM-1 antibody. 
   
   
       39 . The method of  claim 38 , wherein the sensor further comprises a binding group acid layer to couple the KIM-1 antibody to the Au-comprising gate. 
   
   
       40 . The method of  claim 39 , wherein the binding group layer comprises thioglycolic acid. 
   
   
       41 . The method of  claim 27 , wherein the sample is aqueous, the target molecule is prostate specific antigen (PSA), the HEMT comprises an Au-comprising gate, and the capture reagent comprises a PSA antibody. 
   
   
       42 . The method of  claim 41 , wherein the sensor further comprises a binding group layer to couple the PSA antibody to the Au-comprising gate. 
   
   
       43 . The method of  claim 42 , wherein the binding group layer comprises thioglycolic acid. 
   
   
       44 . The method of  claim 27 , wherein the sample is exhaled breath condensate, the target molecule is glucose, the HEMT comprises a gate dielectric layer comprising nanorods, and the capture reagent comprises glucose oxidase immobilized on the nanorods. 
   
   
       45 . The method of  claim 44 , wherein the nanorods comprise a metal oxide. 
   
   
       46 . The method of  claim 44 , wherein the metal oxide comprises at least one of ZnO, SnO, TiO 2 , MgO, ZnMgO, and In 2 O 3 . 
   
   
       47 . The method of  claim 27 , wherein the sample is exhaled breath condensate, saliva, urine, blood, other biological fluids, or other aqueous solutions. 
   
   
       48 . A high electron mobility transistor (HEMT) based sensor for one or more target molecules in a sample, comprising:
 an HEMT having a two layer structure of group semiconductor materials, the first layer of the two layer structure being a layer having a first ionic strength and the second layer of the two layer structure being a strained layer on the first layer and having a second ionic strength different than the first ionic strength, where a high density electron sheet carrier concentration channel of a 2-dimensional gas channel is induced by piezoelectric polarization of the strained layer and spontaneous polarization of the different ionic strengths between the second layer and the strained layer; and   at least one capture reagent on a gate region of the HEMT.