Methods and devices for detection of pathogens

Abstract

In one aspect, a method of detecting a pathogen, e.g., Listeria bacterium, Chlamydia bacteria, gonorrhea bacteria and/or HPV, in a sample is disclosed, which comprises bringing a sample into contact with a graphene layer functionalized with an antibody exhibiting specific binding to the pathogen, monitoring electrical resistance of said antibody-functionalized graphene layer in response to interaction with said sample, and detecting presence of the pathogen in said sample by detecting a change in said electrical resistance indicative of interaction of the pathogen with said antibody-functionalized graphene layer. For example, a decrease of the electrical resistance of the graphene layer can indicate the presence of the pathogen in the sample under study. In some embodiments, a method according to the present teachings is capable of detecting pathogens, such as Listeria bacteria, Chlamydia bacteria, gonorrhea bacteria and HPV in a sample at a concentration as low as 4 cfu per 100 grams of a sample.

1 . (canceled) 
     
     
         2 . A sensor for detecting a pathogen in a sample, comprising
 a substrate,   a graphene layer deposited on a surface of the substrate, wherein the graphene layer is functionalized with a plurality of antibodies exhibiting specific binding affinity to a pathogen forming an antibody-functionalized graphene layer,   a microfluidic delivery device coupled to the antibody-functionalized graphene layer for delivery of a fluid sample thereto,   wherein the microfluidic device comprises:
 two fluid reservoirs and a fluid channel connecting said two reservoirs, wherein the fluid channel is configured such that at least a portion thereof is in fluid contact with at least a portion of the graphene layer. 
   
     
     
         3 . The sensor of  claim 2 , further comprising a reference electrode disposed in proximity of the antibody-functionalized graphene layer. 
     
     
         4 . The sensor of  claim 3 , wherein the reference electrode is disposed at a distance in a range of about 50 microns to about 2 mm from the antibody-functionalized graphene layer. 
     
     
         5 . The sensor of  claim 3 , further comprising an AC voltage source for applying an AC voltage to the reference electrode. 
     
     
         6 . The sensor of  claim 5 , wherein the AC voltage source is configured to apply the AC voltage having a frequency in a range of about 1 kHz to about 1 MHz. 
     
     
         7 . The sensor of  claim 5 , wherein the AC voltage source is configured to apply the AC voltage having a frequency in a range of about 10 kHz to about 1 MHz. 
     
     
         8 . The sensor of  claim 5 , wherein the AC voltage source is configured to apply the AC voltage having a frequency in a range of about 10 kHz to about 500 kHz. 
     
     
         9 . The sensor of  claim 5 , wherein the AC voltage has an amplitude in a range of about 1 millivolts to about 3 volts. 
     
     
         10 . The sensor of  claim 5 , wherein a DC offset is further applied to the reference electrode. 
     
     
         11 . The sensor of  claim 2 , wherein the substrate is any of a semiconductor and glass. 
     
     
         12 . The sensor of  claim 2 , further comprising a pair of conductive pads electrically coupled to the graphene layer configured to facilitate measurement of an electrical resistance of the graphene layer in response to interaction with the sample. 
     
     
         13 . A method of forming a sensor for detecting a pathogen in a sample, comprising
 providing a substrate,   providing a graphene layer deposited on a surface of the substrate   forming an antibody-functionalized graphene layer by functionalizing the graphene layer with a plurality of antibodies exhibiting specific binding affinity to a pathogen;   providing a microfluidic delivery device coupled to the antibody-functionalized graphene layer for delivery of a fluid sample thereto,   wherein the microfluidic device comprises:
 two fluid reservoirs and a fluid channel connecting said two reservoirs, wherein the fluid channel is configured such that at least a portion thereof is in fluid contact with at least a portion of the graphene layer. 
   
     
     
         14 . The method of  claim 13 , further comprising providing a reference electrode disposed in proximity of the antibody-functionalized graphene layer. 
     
     
         15 . The method of  claim 14 , wherein the reference electrode is disposed at a distance in a range of about 50 microns to about 2 mm from the antibody-functionalized graphene layer. 
     
     
         16 . The method of  claim 14 , further comprising providing an AC voltage source for applying an AC voltage to the reference electrode. 
     
     
         17 . The method of  claim 16 , wherein the AC voltage source is configured to apply the AC voltage having a frequency in a range of about 1 kHz to about 1 MHz. 
     
     
         18 . The method of  claim 16 , wherein the AC voltage source is configured to apply the AC voltage having a frequency in a range of about 10 kHz to about 1 MHz. 
     
     
         19 . The method of  claim 16 , wherein the AC voltage has an amplitude in a range of about 1 millivolts to about 3 volts. 
     
     
         20 . The method of  claim 16 , wherein a DC offset is further applied to the reference electrode. 
     
     
         21 . The method of  claim 13 , further comprising providing a pair of conductive pads electrically coupled to the graphene layer configured to facilitate measurement of an electrical resistance of the graphene layer in response to interaction with the sample.