Digital control of on-chip magnetic particle assay

Abstract

An assay system and method for use in the field of chemical testing is disclosed. The assay system can be used for filtering whole blood for testing on an integrated circuit containing digital control functionality.

We claim: 
     
         1 . An assay system ( 10 ) for generating presentable assay information from an aqueous sample ( 5 ), comprising:
 a filter ( 6 ) capable of trapping or blocking particulate matter in an aqueous sample ( 5 );   a delivery capillary ( 14 ) that fluidically connects the filter ( 6 ) to a surface capillary ( 15 );   a first sedimentation capillary ( 13 ) placed vertically above an integrated circuit  12  a surface capillary ( 15 ) that fluidically connects the delivery capillary ( 14 ) to the sedimentation capillary ( 13 );   a dry sphere ( 3 ) placed at the top of the first sedimentation capillary ( 13 ), wherein the dry sphere contains magnetic particles;   magnetic particle sensors embedded in the integrated circuit ( 12 ) at the bottom of the first sedimentation capillary ( 13 ), wherein the magnetic particle sensors are capable of detecting magnetic particles specifically bound to the surface of the integrated circuit; and   a display ( 1 ) for displaying presentable assay information.   
     
     
         2 . The system of  claim 1 , configured to allow a user to take a photograph of the display ( 1 ) to retrieve the presentable assay information. 
     
     
         3 . The system of  claim 2 , wherein the presentable assay information retrieved by taking the photograph of the display ( 1 ) binds to a patient ID in a secure manner. 
     
     
         4 . The system of  claim 1 , wherein a magnetic particle sensor detects a single specific molecular interaction between the surface ( 12 ) of an IC ( 7 ) and a magnetic particle. 
     
     
         5 . The system of  claim 4 , wherein an array of the magnetic particle sensors is configured to count the number of specific molecular interactions in the sensing area on the surface ( 12 ) of the IC ( 7 ). 
     
     
         6 . The system of  claim 1 , wherein a dry calibrant located on the surface ( 7 ) of the integrated circuit ( 12 ) such that the dry calibrant will be rehydrated by the aqueous sample and flow into a second sedimentation capillary ( 63 ) but not into the first sedimentation capillary ( 13 ). 
     
     
         7 . The system of  claim 6 , wherein the signals from the first sedimentation capillary ( 13 ) and the second sedimentation capillary ( 63 ) is used to calibrate the native target signal. 
     
     
         8 . The system of  claim 1 , wherein the third sedimentation capillary ( 64 ) has a different height than the first sedimentation capillary ( 13 ). 
     
     
         9 . The system of  claim 8 , wherein the signal from the first sedimentation capillary ( 13 ) and the third sedimentation capillary ( 64 ) is used to measure the background signal. 
     
     
         10 . The system in  claim 1 , wherein a passive unidirectional valve eliminates and/or reduces the suck-back flow resulting from aqueous sample evaporation through the filter ( 6 ). 
     
     
         11 . The system in  claim 1 , wherein the magnetic particle sensors comprise optical sensors, and wherein multiple light sources producing illuminations of different color are used to identify magnetic particles of different color. 
     
     
         12 . The system of  claim 11 , wherein magnetic particles of different color are coated with reagents that react with different target in a multiplexed format. 
     
     
         13 . The system of  claim 1 , wherein a cuvette ( 30 ) is placed at the top of sedimentation capillary ( 13 ) to keep the dry sphere ( 3 ) motionless.