Magnetic particle based biosensor

Abstract

A biosensor system and method of its use for detecting particles on the surface of an integrated circuit is disclosed. The system can include a light source and a plurality of optical sensors formed on an integrated circuit. The particles can be positioned the surface of the integrated circuit whereby the particles can cast a shadow or shadows that reduces the amount of light transmitted from the light source to the optical sensors. The surface of the integrated circuit can include one or more optical sensing areas whereby the presence of one or more particles may significantly or measurably reduce the amount of light incident on one or more optical sensor.

I claim: 
     
         1 . A device for detecting a target analyte in an aqueous sample comprising;
 an integrated circuit;   a first separation conductor and a second separation conductor embedded in the integrated circuit;   a first current and a second current passing through the first and second separation conductors, respectively; and   a first and second magnetic particles;   wherein the first current passing through the first separation conductor generates a first magnetic field that pulls the first magnetic particle with a first force;   wherein the second current passing through the second separation conductor generates a second magnetic field that pulls the second magnetic particle with a second force;   wherein the first and second current are of different intensity; and   wherein the first and second magnetic particles are pulled with different forces.   
     
     
         2 . The device of  claim 1 , wherein sensors embedded in the integrated circuit detect magnetic particles on the surface of the integrated circuit. 
     
     
         3 . The device of  claim 1 , wherein the sensors are optical. 
     
     
         4 . The device of  claim 1 , wherein the sensors are magnetic. 
     
     
         5 . The device of  claim 1 , wherein the sensors are sized to detect one magnetic particle 
     
     
         6 . The device of  claim 1 , wherein the sensors detect magnetic particles specifically bound to the surface of the IC. 
     
     
         7 . The device of  claim 1 , further comprising concentration conductors embedded in the integrated circuit , and wherein magnetic concentration forces produced by current passing through the concentration conductors are sufficient to attract the magnetic particles to the sensing areas. 
     
     
         8 . The device of  claim 1 , wherein the aqueous sample is filtered and wicked via capillary action through a capillary onto the surface of the integrated circuit; 
     
     
         9 . The device of  claim 8 , wherein the aqueous sample can rehydrate the dry reagent and wherein the magnetic particles can be released and sediment through the aqueous sample to the surface of the integrated circuit; 
     
     
         10 . The device of  claim 9 , wherein the magnetic particles that react with one or more target species in aqueous sample bind specifically to the surface of the integrated circuit. 
     
     
         11 . The device of  claim 10 , wherein the first force can be strong enough to displace the first magnetic particle from atop the first sensor