Single channel cartridge device for coagulation assays in fluid samples

Abstract

The present invention relates to analytical testing devices comprising a single channel with micro-environment sensors and methods for assaying coagulation in a fluid sample applied to the micro-environment sensors, and in particular, to performing coagulation assays using a single channel with micro-environment sensors in a point of care test cartridge. For example, the present invention may be directed to a sample analysis cartridge including an inlet chamber configured to receive a biological sample and a conduit fluidically connected to the inlet chamber. The conduit includes a sensor chip including a first micro-environment sensor and a second microenvironment sensor, and a fluid lock valve. The sample analysis cartridge further includes a pump configured to push the biological sample over the first micro-environment sensor and the second microenvironment sensor to the fluidic lock valve such that the biological sample is positioned over the first micro-environment sensor and the second micro-environment sensor.

We claim: 
     
         1 . A sensing device comprising:
 a conduit configured to receive a fluid sample;   a first analyte sensor positioned within the conduit;   a second analyte sensor positioned within the conduit;   a first conductivity sensor comprising two electrodes positioned upstream of a midpoint of the first analyte sensor; and   a second conductivity sensor comprising two electrodes positioned downstream of a midpoint of the second analyte sensor.   
     
     
         2 . The sensing device of  claim 1 , wherein the first analyte sensor is an amperometric sensor or an optical sensor and the second analyte sensor is an amperometric sensor or an optical sensor. 
     
     
         3 . The sensing device of  claim 1 , wherein the conduit, the first analyte sensor, the second analyte sensor, the first conductivity sensor and the second conductivity sensor are fabricated on a single silicon chip, and wherein the first analyte sensor and the second analyte sensor are located on different vertical planes of the single silicon chip. 
     
     
         4 . The sensing device of  claim 1 , wherein a first electrode of the two electrodes of the first conductivity sensor is electrically wired to a conductometric low pin, and a second electrode of the two electrodes of the first conductivity sensor is electrically wired to a conductometric high pin, such that an electrical resistance between each of the two electrodes of the first conductivity sensor indicates position of a front of the fluid sample in the conduit. 
     
     
         5 . The sensing device of  claim 4 , wherein a first electrode of the two electrodes of the second conductivity sensor is electrically wired to the conductometric low pin and a second electrode of the two electrodes of the second conductivity sensor is electrically wired to the conductometric high pin, such that an electrical resistance between each of the two electrodes of the second conductivity sensor indicates a position of the front of the fluid sample in the conduit. 
     
     
         6 . The sensing device of  claim 1 , wherein the two electrodes of the first conductivity sensor and the two electrodes of the second conductivity sensor lie perpendicularly to a length of the conduit. 
     
     
         7 . The sensing device of  claim 1 , wherein the first analyte sensor is an activated partial thromboplastin (aPTT) time sensor and the second analyte sensor is a prothrombin time (PT) sensor. 
     
     
         8 . A sensing device comprising:
 a single planar substrate;   a conduit configured to receive a fluid sample;   a first analyte sensor formed on the single planar substrate and positioned within the conduit;   a second analyte sensor formed on the single planar substrate and positioned within the conduit;   a reference electrode formed on the single planar substrate and positioned within the conduit between the first analyte sensor and the second analyte sensor;   a first conductivity sensor formed on the single planar substrate and positioned within the conduit upstream of a midpoint of the first analyte sensor, wherein the first conductivity sensor comprises a first pair of electrodes; and   a second conductivity sensor formed on the single planar substrate and positioned within the conduit downstream of a midpoint of the second analyte sensor, wherein the second conductivity sensor comprises a second pair of electrodes.   
     
     
         9 . The sensing device of  claim 8 , wherein the first analyte sensor is an amperometric sensor or an optical sensor and the second analyte sensor is an amperometric sensor or an optical sensor. 
     
     
         10 . The sensing device of  claim 8 , wherein the single planar substrate is a silicon chip. 
     
     
         11 . The sensing device of  claim 10 , wherein the first analyte sensor and the second analyte sensor are located on different vertical planes of the silicon chip. 
     
     
         12 . The sensing device of  claim 8 , wherein a first electrode of the first pair of electrodes is electrically wired to a conductometric low pin, and a second electrode of the first pair of electrodes is electrically wired to a conductometric high pin, such that an electrical resistance between each electrode of the first pair of electrodes indicates position of a front of the fluid sample in the conduit. 
     
     
         13 . The sensing device of  claim 12 , wherein a first electrode of the second pair of electrodes is electrically wired to a conductometric low pin, and a second electrode of the second pair of electrodes is electrically wired to a conductometric high pin, such that an electrical resistance between each electrode of the second pair of electrodes indicates position of a front of the fluid sample in the conduit. 
     
     
         14 . The sensing device of  claim 8 , wherein the first analyte sensor is an activated partial thromboplastin (aPTT) time sensor and the second analyte sensor is a prothrombin time (PT) sensor. 
     
     
         15 . The sensing device of  claim 8 , wherein the first pair of electrodes and the second pair of electrodes lie perpendicularly to a length of the conduit. 
     
     
         16 . A method for determining a position of a fluid in a conduit of a sensing device, the method comprising:
 receiving a fluid in an inlet chamber;   moving the fluid from the inlet chamber to a conduit using a pump;   determining arrival of the fluid at a position upstream of a first analyte sensor positioned within the conduit with a first conductivity sensor, comprising a first pair of electrodes and positioned within the conduit upstream of a midpoint of the first analyte sensor, based on a first change in measured conductivity; and,   
       determining arrival of the fluid at a position downstream of a second analyte sensor positioned within the conduit with a second conductivity sensor, comprising a second pair of electrodes and positioned within the conduit downstream of a midpoint of the second analyte sensor, based on a second change in measured conductivity. 
     
     
         17 . The method of  claim 16 , wherein a first electrode of the first pair of electrodes is electrically wired to a conductometric low pin, and a second electrode of the first pair of electrodes is electrically wired to a conductometric high pin. 
     
     
         18 . The method of  claim 17 , wherein a first electrode of the second pair of electrodes is electrically wired to a conductometric low pin, and a second electrode of the second pair of electrodes is electrically wired to a conductometric high pin. 
     
     
         19 . The method of  claim 16 , wherein the first analyte sensor is an activated partial thromboplastin (aPTT) time sensor and the second analyte sensor is a prothrombin time (PT) sensor. 
     
     
         20 . The method of  claim 16 , wherein the conduit, the first analyte sensor, the second analyte sensor, the first conductivity sensor and the second conductivity sensor are fabricated on a single silicon chip.