Whole Virus Quantum Mechanical Tunneling Current and Electronic Sensors

Abstract

A field effect transistor (FET) biosensor for virus detection of a selected virus within a sample volume is disclosed. The FET comprises a semiconductor substrate, a source and drain electrode on the substrate, the electrodes spaced to form a channel. A gate electrode carried on the substrate and located in the channel between the source and drain electrodes. An insulating layer is coupled to a top surface of the gate electrode and a bottom surface of the source and drain electrodes, with an open channel above the insulating layer. A channel material is coupled to the insulating layer. Aptamers are oriented within the open channel to bind to the channel material and with the selected virus to enable a detection of the selected virus by the FET biosensor based on a change in drain-source current at a selected gate voltage.

What is claimed is: 
     
         1 . A field effect transistor (FET) biosensor for virus detection of a selected virus within a sample volume, comprising:
 a semiconductor substrate;   a source electrode on the semiconductor substrate;   a drain electrode on the semiconductor substrate and spaced apart from the source electrode;   a gate electrode carried on the semiconductor substrate and located between the source electrode and the drain electrode, with the gate electrode recessed below the source electrode and the drain electrode to form an open channel;   an insulating layer coupled to a top surface of the gate electrode and a bottom surface of the source electrode and the drain electrode such that the insulating layer is located between the gate electrode and source electrode and between the gate electrode and the drain electrode, the insulating layer forming a bottom of the open channel;   a channel material coupled to the insulating layer such that the sample volume can be oriented within the open channel; and   molecular recognition groups oriented within the open channel, the molecular recognition groups configured to bind with the selected virus to change a current (I DS ) between the drain electrode and the source electrode or a channel conductivity at a selected voltage (V GS ) applied to the gate electrode relative to the source electrode to enable a detection of the selected virus by the FET biosensor based on the change in I DS  at the selected voltage or the channel conductivity at the selected voltage.   
     
     
         2 . The FET biosensor of  claim 1 , wherein the insulating layer is comprised of one or more of silicon dioxide, hafnium dioxide, nitride-oxide, titanium oxide, or composites thereof. 
     
     
         3 . The FET biosensor of  claim 1 , wherein the source electrode, gate electrode, and drain electrode are comprised of one or more conductors comprising silver, gold, copper, platinum, aluminum, zinc, cobalt, nickel, tungsten, or ruthenium. 
     
     
         4 . The FET biosensor of  claim 1 , wherein:
 the source, drain, and gate electrodes have a thickness between approximately 50 nanometers (nm) and 250 nm; and   the insulating layer has a thickness of between approximately 5 nm and 20 nm.   
     
     
         5 . The FET biosensor of  claim 1 , wherein a distance between the source electrode and the drain electrode creates a channel width of approximately 500 nanometers (nm) and 2000 nm. 
     
     
         6 . The FET biosensor of  claim 1 , wherein the channel material is one or more of:
 a zeolite layer formed in the channel and having at least a portion of the molecular recognition groups therein;   a thin gold film having a thickness between approximately 20 and 40 nanometers deposited on the insulating layer in the channel and having at least a portion of the molecular recognition groups functionalized on the thin gold film; or   gold nano particles having a diameter between approximately 25 nm and 75 nm, the gold nano particles attached to at least a portion of the molecular recognition groups.   
     
     
         7 . The FET biosensor of  claim 1 , wherein the sample volume comprises one or more of:
 an aptamer buffer solution having between approximately 0.5 micro Mole (uM) and 5 uM concentration;   a stock solution of virus; or   a solution of gold nanoparticles functionalized with at least a portion of the aptamers.   
     
     
         8 . The FET biosensor of  claim 1 , wherein the molecular recognition groups are at least one of aptamers, antigens, and antibodies. 
     
     
         9 . The FET biosensor of  claim 1 , wherein the selected virus is one or more of:
 a SARS-COV-1 virus;   a SARS-COV-2 virus;   a Zika virus; or   a coronavirus.   
     
     
         10 . The FET biosensor of  claim 1 , wherein at least a portion of the molecular recognition groups are suspended within the open channel in one or more of a dried suspension, a hydrogel, or a dried network of functionalized nanoparticles. 
     
     
         11 . The FET biosensor of  claim 1 , wherein at least a portion of the molecular recognition groups are functionalized to at least one of the bottom of the open channel, the drain electrode and the source electrode. 
     
     
         12 . The FET biosensor of  claim 1 , wherein the open channel is configured to receive a drop casted material that includes one or more of the molecular recognition groups, the selected virus, and gold nanoparticles. 
     
     
         13 . A method of detecting a virus, comprising:
 exposing a sensor surface to a fluid sample containing a suspected virus, wherein the sensor surface is modified with aptamers selective for binding to the virus;   measuring an impedance spectrum of the sensor surface;   comparing the measured impedance spectrum with an impedance spectrum indicating the presence of the virus bound to the aptamer; and   outputting a detection signal.   
     
     
         14 . The method of  claim 13 , wherein the impedance of the sensor surface is measured through a pair of electrodes in contact with the sensor surface. 
     
     
         15 . The method of  claim 14 , wherein the pair of electrodes are an interdigital transducer. 
     
     
         16 . The method of  claim 13 , wherein the virus is ZIKV or SARS-CoV-2.