Assays

Abstract

A method for assaying a sample for each of multiple analytes is described. The method includes contacting an array of spaced-apart test zones with a liquid sample (e.g., whole blood). The test zones disposed within a channel of a microfluidic device. The channel is defined by at least one flexible wall and a second wall which may or may not be flexible. Each test zone comprising a probe compound specific for a respective target analyte. The microfluidic device is compressed to reduce the thickness of the channel, which is the distance between the inner surfaces of the walls within the channel. The presence of each analyte is determined by optically detecting an interaction at each of multiple test zones for which the distance between the inner surfaces at the corresponding location is reduced. The interaction at each test zone is indicative of the presence in the sample of a target analyte. Capillary structures of the devices or used in the methods may comprise a matrix and the devices may comprise control elements and methods for assaying of sample may use corresponding controlling activities.

1 - 191 . (canceled) 
     
     
         192 . A device for detecting an analyte in a sample, comprising:
 a cartridge having:
 a microfluidic channel comprising a first end and a second end and between the first and the second end an inlet region, a detection region in fluid communication with the inlet region, and an opening configured to vent the microfluidic channel; 
 a microfluidic flow path having an at least partially deformable wall and in fluid communication with the detection region of the channel. 
   
     
     
         193 . The device of  claim 192 , wherein the opening is an opening in a wall surrounding the microfluidic channel. 
     
     
         194 . The device of  claim 192 , wherein the opening is in fluid communication with ambient fluid surrounding the cartridge. 
     
     
         195 . The device of  claim 192 , wherein the opening is located between the inlet region and the detection region. 
     
     
         196 . The device of  claim 192 , wherein the opening is configured to remove gas from the inlet region during filling of the device with the sample. 
     
     
         197 . The device of  claim 192 , wherein the opening is closable. 
     
     
         198 . The device of  claim 192 , wherein the inlet region is movable within the microfluidic channel. 
     
     
         199 . The device of  claim 198 , wherein the inlet region is movable with respect to the opening. 
     
     
         200 . The device of  claim 198 , wherein the inlet region is movable along a longitudinal axis of the microfluidic channel. 
     
     
         201 . The device of any of  claim 198 , wherein the opening, in a first relative position of the inlet region within the microfluidic channel, is in fluid communication with the inlet region, and, in a second relative position of the inlet region within the microfluidic channel, is closed. 
     
     
         202 . The device of  claim 201 , wherein said device further comprises a cap having a sealing member configured to seal with the inlet region, wherein the cap is arranged such that closing of the cap moves the inlet region from the first relative position within the microfluidic channel to the second relative position within the microfluidic channel to form a closed fluid circuit including the inlet region, the detection region and the microfluidic flow path. 
     
     
         203 . A method of detecting an analyte comprising:
 introducing a liquid sample into a first end of a microfluidic channel comprising the first end and a second end and between the first and the second end an opening configured to vent the microfluidic channel, thereby forming a contiguous liquid slug enclosed by the channel and bounded at a first end by a transport fluid;   forming a fluid circuit such that the opening is closed and the transport fluid provides fluid communication between the first and second ends of the liquid slug; and   applying a differential pressure to the first and second ends of the liquid slug via the transport fluid.   
     
     
         204 . The method of  claim 203 , wherein a portion of the fluid circuit is formed by an elastically deformable wall. 
     
     
         205 . The method of  claim 203 , wherein applying a differential pressure to the first and second ends of the liquid slug includes compressing the elastically deformable wall. 
     
     
         206 . A method, comprising:
 introducing a liquid sample into a first end of a microfluidic channel comprising the first end and a second end and between the first and the second end an opening configured to vent the microfluidic channel, thereby forming a contiguous liquid slug enclosed by the channel and bounded at a first end by a transport fluid;   forming a fluid circuit such that the opening is closed and the transport fluid provides fluid communication between the first and second ends of the liquid slug,   forming a mixture comprising at least a portion of the liquid sample and an optical label by applying a differential pressure to the first and second ends of the liquid slug via the transport fluid,   forming multiple complexes, each complex comprising one of the multiple particles and at least one of the optical labels, and   detecting complexes present within a subset of the mixture.   
     
     
         207 . The method of  claim 206 , wherein the particles are cells and the optical labels are fluorescent labels. 
     
     
         208 . The method of  claim 206 , wherein the opening is an opening in a wall surrounding the microfluidic channel. 
     
     
         209 . The method of  claim 206 , wherein the opening is in fluid communication with ambient fluid surrounding the microfluidic channel during introducing the liquid sample. 
     
     
         210 . The method of  claim 206 , wherein the opening is located between the inlet and the detection region. 
     
     
         211 . The method of  claim 206 , wherein the inlet is movable within the microfluidic channel. 
     
     
         212 . The method of  claim 211 , wherein the inlet region is movable with respect to the opening. 
     
     
         213 . The method of  claim 211 , wherein the inlet region is movable along a longitudinal axis of the microfluidic channel. 
     
     
         214 . The method of  claim 211 , wherein the opening, in a first relative position of the inlet region within the microfluidic channel, is in fluid communication with the inlet region, and, in a second relative position of the inlet region within the microfluidic channel, is closed. 
     
     
         215 . The method of  claim 214 , wherein said device further comprises a cap having a sealing member configured to seal with the inlet region, wherein closing of the cap moves the inlet region from the first relative position within the microfluidic channel to the second relative position within the microfluidic channel to form a closed fluid circuit including the inlet region and the detection region. 
     
     
         216 . The method of  claim 206 , further comprising optically detecting a signal indicative of an amount of complex present within a subset of the liquid sample, the subset being present within a detection region of the microfluidic device.