Biosensor apparatus and methods of use

Abstract

Disclosed herein are methods and devices for detecting the presence of an analyte of interest. A biosensor device can include a reaction chamber and an electrochemical detection chamber. The reaction chamber can include at least one immobilized binding site and a probe conjugate adapted to bind to at least one of the target analyte and the immobilized binding site, while the detection chamber can include electrodes for detecting an electrochemical reaction. If present, the target analyte in the fluid sample results in a change in the amount of probe conjugate bound in the reaction chamber, which can be detected electrochemically in the detection chamber.

1 . A biosensor for use in detecting a target analyte in a fluid sample, the device comprising: 
 a reaction chamber including an immobilized binding site and a probe conjugate, wherein the probe conjugate comprises a binding partner adapted to bind to the immobilized binding site;    a detection chamber including electrodes for detecting an electrochemical reaction in the detection chamber; and    a fluid passageway between the reaction chamber and the detection chamber, wherein, the presence or absence of a target analyte in the fluid sample results in a change in the amount of probe conjugate bound in the reaction chamber, the change detectable with an electrochemical reaction in the detection chamber.    
   
   
       2 . The biosensor of  claim 1 , wherein the immobilized binding site is an antigen and the binding partner is an antibody.  
   
   
       3 . The biosensor of  claim 1 , wherein the immobilized binding site is an antibody and the binding partner is an antigen.  
   
   
       4 . The biosensor of  claim 1 , further comprising a filling chamber adapted to be filled via capillary action.  
   
   
       5 . The biosensor of  claim 4 , wherein the capillary dimension of the reaction chamber is smaller in size than that of the filling chamber.  
   
   
       6 . The biosensor of  claim 1 , wherein the detection chamber includes a vent.  
   
   
       7 . The biosensor of  claim 6 , wherein the vent can be opened by piercing an outer layer of the device.  
   
   
       8 . The biosensor of  claim 6 , wherein the vent can be opened by removing a portion of an outer layer of the device.  
   
   
       9 . The biosensor of  claim 6 , wherein the vent can be opened by tearing along a perforation.  
   
   
       10 . The biosensor of  claim 1 , wherein the reaction chamber includes an opening to the atmosphere.  
   
   
       11 . The biosensor of  claim 1 , wherein immobilized binding site and the probe conjugate are positioned on different surfaces within the reaction chamber.  
   
   
       12 . The biosensor of  claim 1 , wherein the immobilized binding site is positioned on at least one magnetic bead.  
   
   
       13 . The biosensor of  claim 12 , wherein the at least one magnetic bead is dried on to an internal surface of the reaction chamber.  
   
   
       14 . The biosensor of  claim 12 , further comprising a magnet.  
   
   
       15 . The biosensor of  claim 14  wherein the magnet is disposed so as to move the at least one magnetic bead to be in intimate contact with the probe conjugate after the fluid sample has been introduced into the reaction chamber.  
   
   
       16 . The biosensor of  claim 1 , wherein the probe conjugate includes an enzyme.  
   
   
       17 . The biosensor of  claim 16 , further comprising a mediator and an enzyme substrate.  
   
   
       18 . An biosensor for use in detecting a target antigen in a fluid sample, the device comprising: 
 a reaction chamber including at least one immobilized binding site including a antibody and a probe conjugate including an antibody adapted to bind to bound target antigen;    a detection chamber including electrodes for detecting an electrochemical reaction in the detection chamber; and    a fluid passageway between the reaction chamber and the detection chamber, wherein, the presence of a target antigen in the fluid sample results in a reduction in the amount of probe conjugate bound in the reaction chamber, the reduction being detectable with an electrochemical reaction in the detection chamber.    
   
   
       19 . A method of detecting a target analyte in a fluid sample, the method comprising the steps of: 
 delivering a sample to a biosensor that includes a reaction chamber and a detection chamber;    allowing a reaction to proceed in the reaction chamber between an immobilized binding site and a probe conjugate;    moving the sample into a detection chamber and electrochemically detecting the level of probe conjugate, wherein the presence of a target analyte in the sample results in an increase or a decrease in the amount of probe conjugate detected in the reaction chamber.    
   
   
       20 . The method of  claim 19 , wherein the immobilized binding site includes a target antigen and the probe conjugate includes an antibody adapted to bind to the target antigen.  
   
   
       21 . The method of  claim 19 , wherein the probe conjugate includes an enzyme.  
   
   
       22 . The method of  claim 19 , wherein the sample is moved from the reaction chamber to the detection chamber via capillary action.  
   
   
       23 . The method of  claim 19 , wherein the step of moving the sample includes opening a vent.  
   
   
       24 . The method of  claim 19 , further comprising the step of quantifying the amount of target antigen in the sample based electrical signals received from the detection chamber.