Methods and Devices for Active Bioassay

Abstract

The present invention provides an active assay method for detecting a biological analyte. According to the method, a probe molecule is immobilized on a surface. An analyte is then placed in fluidic connection with the probe molecule on the surface. A force is then applied to the analyte to move it toward the surface to facilitate contact and possibly binding of the analyte to the probe. Optionally, another force can be applied or the force can be reversed, to remove unbound or weakly bound analyte from the surface. Analyte that remains bound to the surface is then detected. The detection can include rolling or sliding beads over an analyte and/or probe on a substrate, and detecting bound beads. The present invention furthermore, provides devices, such as electrophoresis apparatuses and biochip assemblies, for carrying out the methods of the invention.

1 - 20 . (canceled) 
     
     
         21 . A method comprising:
 a. providing a first probe molecule immobilized on one of:
 i. a substrate; and 
 ii. a magnetic particle; 
   b. contacting an analyte to said first probe molecule to capture said analyte; and   c. binding the captured analyte to a second probe molecule immobilized on the other of:
 i. said substrate; and 
 ii. said magnetic particle. 
   
     
     
         22 . The method of  claim 21 , wherein said substrate comprises at least one of the following:
 a. a glass plate;   b. a plastic plate;   c. a solid support coated with a polymer film;   c. a solid support coated with a gel layer; and   g. at least one combination of the above.   
     
     
         23 . The method of  claim 21 , wherein said substrate is transparent. 
     
     
         24 . The method of  claim 21 , wherein at least one of said first probe molecule and said second probe molecule includes at least one of an amino acid and a nucleotide. 
     
     
         25 . The method of  claim 21 , wherein at least one of said first probe molecule and said second probe molecule are immobilized using at least one linker. 
     
     
         26 . The method of  claim 21 , wherein at least one of said first probe molecule and said second probe molecule is immobilized as an array. 
     
     
         27 . The method of  claim 26 , wherein said array comprises at least two different probe molecules. 
     
     
         28 . The method of  claim 21 , further comprising applying a magnetic field to move said magnetic particle towards said substrate, said captured analyte binding to said second probe molecule. 
     
     
         29 . The method of  claim 28 , wherein said magnetic field comprises an uneven localized magnetic field. 
     
     
         30 . The method of  claim 29 , further comprising forming a stack of magnetic particles over a portion of said substrate. 
     
     
         31 . The method of  claim 30 , wherein said uneven localized magnetic field moves a least a portion of said stack of magnetic particles. 
     
     
         32 . The method of  claim 28 , wherein said magnetic field comprises an uneven magnetic field. 
     
     
         33 . The method of  claim 32 , wherein said uneven magnetic field causes said magnetic particle to contact said substrate. 
     
     
         34 . The method of  claim 33 , wherein a second force moves said magnetic particle over the surface of said substrate. 
     
     
         35 . The method of  claim 34 , wherein said force comprises fluid flow. 
     
     
         36 . The method of  claim 28 , further comprising reversing said magnetic field to separate unlinked or weakly linked magnetic particles. 
     
     
         37 . The method of  claim 21 , further comprising detecting a connection between said magnetic bead and said substrate through said analyte. 
     
     
         38 . The method of  claim 37 , comprising employing light scattering to detect said connection. 
     
     
         39 . The method of  claim 21 , wherein said contacting comprises applying a force to said analyte to move said analyte into contact with one of said probe molecules. 
     
     
         40 . The method of  claim 21 , wherein said analyte is electrically charged.