Method for Sensing a Substance to be Detected in a Sample

Abstract

A single-electron transistor comprising at least a substrate, a source electrode and a drain electrode formed on top of the substrate opposing to each other, and a channel arranged between the source electrode is disclosed wherein the channel is composed of ultra fine fibers. By having such a constitution, a sensor can have excellent sensitivity.

1 . A method for sensing a substance to be detected in a sample by means of a sensor at least provided with a substrate, and a channel having a source electrode and a drain electrode formed with a certain interval and opposite one another on a first insulating membrane formed on top of the substrate, the method comprising the steps of:
 composing the channel of ultra fine fibers;   forming a second insulating membrane in a portion of the substrate on an opposite side to a position where the channel is located;   forming a back gate electrode on an outer side of the second insulating membrane;   modifying the second insulating membrane by hemagglutinin;   intervening the sample between the modified portion and the back gate electrode;   applying a gate voltage to the back gate electrode; and   detecting a substance that interacts with the hemagglutinin in the sample by change in current value between the source electrode and the drain electrode.   
     
     
         2 . The method for sensing a substance to be detected in a sample according to  claim 1 , wherein the hemagglutinin modifies the second insulating membrane with which {N-[5-(3′-Maleimidopropylamino)-1-carboxypentyl]iminodiacetic acid} has been bonded. 
     
     
         3 . The method for sensing a substance to be detected in a sample according to  claim 2 , wherein the hemagglutinin modifies the {N-[5-(3′-Maleimidopropylamino)-1-carboxypentyl]iminodiacetic acid} with which a divalent positive ion has been reacted. 
     
     
         4 . A method for sensing a substance to be detected in a sample by means of a sensor at least provided with a substrate, and a channel having a source electrode and a drain electrode formed with a certain interval and opposite one another on a first insulating membrane formed on top of the substrate, the method comprising the steps of:
 composing the channel of ultra fine fibers;   forming a second insulating membrane in a portion of the substrate on an opposite side to a position where the channel is located;   forming a back gate electrode on an outer side of the second insulating membrane;   modifying the second insulating membrane by calmodulin;   intervening the sample between the modified portion and the back gate electrode;   applying a gate voltage to the back gate electrode; and   detecting a substance that interacts with the calmodulin in the sample by change in current value between the source electrode and the drain electrode.   
     
     
         5 . The method for sensing a substance to be detected in a sample according to  claim 4 , wherein the calmodulin modifies the second insulating membrane with which {N-[5-(3′-Maleimidopropylamino)-1-carboxypentyl]iminodiacetic acid} has been bonded. 
     
     
         6 . The method for sensing a substance to be detected in a sample according to  claim 4 , wherein the calmodulin modifies the {N-[5-(3′-Maleimidopropylamino)-1-carboxypentyl]iminodiacetic acid} with which a divalent positive ion has been reacted. 
     
     
         7 . The method for sensing a substance to be detected in a sample according to  claim 1 ,
 wherein, subsequent to the sample is dropped between the modified portion and the back gate electrode, and a solvent of the sample is then evaporated, thereby, the substance to be detected is detected.   
     
     
         8 . The method for sensing a substance to be detected in a sample according to  claim 1 ,
 wherein, subsequent to the sample is dropped between the modified portion and the back gate electrode, and a solvent of the sample is then frozen, thereby, the substance to be detected is detected.   
     
     
         9 . The method for sensing a substance to be detected in a sample according to  claim 4 ,
 wherein, subsequent to the sample is dropped between the modified portion and the back gate electrode, and a solvent of the sample is then evaporated, thereby, the substance to be detected is detected.   
     
     
         10 . The method for sensing a substance to be detected in a sample according to  claim 4 ,
 wherein, subsequent to the sample is dropped between the modified portion and the back gate electrode, and a solvent of the sample is then frozen, thereby, the substance to be detected is detected.