Method and apparatus for controlling reactions

Abstract

The invention relates to a method and an apparatus for performing an assay on chemical, biochemical, or biological fluids. The apparatus includes an assay chamber for fluid reactions and a centrifugal force activated-valve for controlling fluid movement through the assay chamber. An active surface can be positioned in the assay chamber to react with fluids passed through the assay chamber. The active surface may contain biomolecular probes. The biomolecular probes can be DNA, DNA fragments, RNA, RNA fragments, reagents, protein, protein fragments, lipids, and lipid fragments. The apparatus is particularly useful when multiple reactions, dilutions, or washing steps are required to determine a final answer. The centrifugal force activated-valve provides positive control over fluid in the assay chamber and allows for repeated use of the same chamber for multiple reaction steps. The apparatus can be disposed of after an assay to eliminate potential contamination from reuse of the same apparatus. Fluids passed through the assay chamber may be recovered for subsequent analysis, processing, or reactions.

1 . A method for performing an assay on a sample using an analytical device having a reusable centrifugal valve and an active surface, the method comprising: 
 introducing a sample into a reaction chamber of the analytical device;    spinning the analytical device at a rotational speed to actuate the centrifugal valve from a stationary closed position to an open actuated position, the open actuated position opening the valve, thereby allowing the sample to exit from the reaction chamber through the valve;    introducing a wash fluid into the reaction chamber; and    spinning the analytical device at a rotational speed to actuate the valve from the stationary closed position to the open actuated position, the open actuated position opening the valve and allowing the wash fluid to exit from the reaction chamber through the valve.    
   
   
       2 . The method of  claim 1 , further comprising after the step of introducing the wash fluid: 
 spinning the analytical device at the first rotational speed to generate a radially outward flow of the wash fluid; then    spinning the analytical device at the rotational speed to actuate the valve from the stationary closed position to the open actuated position and allowing the wash fluid to exit from the reaction chamber through the valve.    
   
   
       3 . The method of  claim 2 , further comprising after spinning to allow the wash fluid to exit: optically scanning the active surface to assay the active surface.  
   
   
       4 . The method of  claim 1  wherein the active surface is not attached to the reaction chamber.  
   
   
       5 . The method of  claim 1  wherein the active surface is attached to the reaction chamber.  
   
   
       6 . The device of  claim 1 , wherein the active surface comprises biomolecular probes.  
   
   
       7 . The device of  claim 1 , wherein the biomolecular probes are selected from the group consisting of DNA, DNA fragments, RNA, RNA fragments, reagents, protein, protein fragments, lipids, and lipid fragments.  
   
   
       8 . A method for performing an assay on a sample using an analytical device having a reusable centrifugal valve and an active surface, the method comprising: 
 introducing a sample into an assay chamber of the analytical device; and    spinning the analytical device at a rotational speed sufficient to actuate the centrifugal valve from a stationary closed position to an open actuated position and allowing the sample to exit from the assay chamber through the centrifugal valve.    
   
   
       9 . The method of  claim 8 , further comprising: distributing the sample to a chamber radially outward from the valve, the chamber operative to contain the sample for further processing.  
   
   
       10 . The method of  claim 9 , further comprising: scanning an optically transparent portion of the analytical device with an optical detection means to assay the active surface.  
   
   
       11 . The method of  claim 8 , further comprising the steps of: 
 washing the active surface by introducing a wash fluid into the assay chamber after spinning the analytical device to remove the sample from the assay chamber;    spinning the analytical device at a first rotational speed to generate a radially outward flow of the wash fluid, the first rotational speed being below a rotational speed necessary to actuate the centrifugal valve from the stationary closed position to the open actuated position, the wash fluid operative to remove un-reacted sample from the active surface and the assay chamber; and    spinning the analytical device at a rotational speed greater than the first rotational speed to actuate the centrifugal valve from the stationary closed position to the open actuated position and allow the wash fluid to exit from the assay chamber through the centrifugal valve.    
   
   
       12 . The method of  claim 11 , further comprising: scanning an optically transparent portion of the analytical device using the optical detection means to assay the active surface.  
   
   
       13 . The method of  claim 12 , further comprising: adding fluid to the assay chamber and spinning the analytical device below the first rotational speed to distribute the fluid; and scanning an optically transparent portion of the analytical device using the optical detection means to assay the active surface.  
   
   
       14 . The method of  claim 8  wherein the active surface is not attached to the reaction chamber.  
   
   
       15 . The method of  claim 8  wherein the active surface is attached to the reaction chamber.  
   
   
       16 . The method of  claim 8 , wherein the active surface comprises biomolecular probes.  
   
   
       17 . The method of  claim 8 , wherein the biomolecular probes are selected from the group consisting of DNA, DNA fragments, RNA, RNA fragments, reagents, protein, protein fragments, lipids, and lipid fragments.  
   
   
       18 - 24 . (canceled)  
   
   
       25 . An analytical device for controlling reactions, comprising: 
 a housing enclosure defining an assay chamber and a fluid discharge port positioned radially outward from the assay chamber and in fluid communication with the assay chamber, the housing enclosure adapted for rotation about an axis;    an active surface in the chamber;    means for introducing fluid into the assay chamber; and    a centrifugally-operated valve in fluid communication with the fluid discharge port, the valve repetitively operable between a stationary position and an actuated position, the valve operative to transition from the stationary position to the actuated position when a centrifugal force generated by rotating the housing enclosure exceeds a predetermined limit, and to transition from the actuated position to the stationary position when the centrifugal force does not exceed the predetermined limit.    
   
   
       26 . The device of  claim 25 , wherein the active surface comprises biomolecular probes.  
   
   
       27 . The device of  claim 26 , wherein the biomolecular probes are selected from the group consisting of DNA, DNA fragments, RNA, RNA fragments, reagents, protein, protein fragments, lipids, and lipid fragments.  
   
   
       28 - 30 . (canceled)