Apparatus and methods for concentrating and seperating particles such as molecules

Abstract

Particles of interest, such as DNA molecules, are injected into a medium by applying a first field. Once in the medium the particles are concentrated by applying one or more fields that cause mobilities of the particles in the medium to vary in a manner that is correlated with motions of the particles. Particle injection and particle concentration may be performed concurrently or in alternation.

1 - 32 . (canceled) 
     
     
         33 . An apparatus for concentrating particles of interest, comprising:
 a buffer reservoir configured to receive a liquid sample;   a gel medium adjacent to the buffer reservoir wherein the particles of interest have a mobility that depends upon at least one of an electric field and a temperature;   at least one electrode configured to provide a first electric field to move particles of interest from the buffer reservoir into the gel medium;   at least two additional electrodes configured to provide time-varying driving fields to concentrate the particles of interest at a focal spot.   
     
     
         34 . The apparatus of  claim 33 , wherein the focal spot is located at a well in the gel medium. 
     
     
         35 . The apparatus of  claim 34 , wherein the well is configured to receive a buffer. 
     
     
         36 . The apparatus of  claim 33 , wherein the focal spot is not adjacent to an electrode. 
     
     
         37 . The apparatus of  claim 33 , wherein the gel medium comprises an oligonucleotide complementary to the particles of interest. 
     
     
         38 . The method of  claim 37 , wherein the gel medium comprises a polymer and the oligonucleotide is covalently bonded to the polymer. 
     
     
         39 . The apparatus of  claim 33 , wherein the gel medium comprises agarose or acrylamide. 
     
     
         40 . The apparatus of  claim 33 , wherein the at least two additional electrodes are configured to modify the mobility of the particles of interest. 
     
     
         41 . The apparatus of  claim 40 , wherein the at least two additional electrodes vary the mobility of the particles of interest with time. 
     
     
         42 . The apparatus of  claim 40 , wherein the at least two additional electrodes are configured to modify the temperature of the gel medium. 
     
     
         43 . The apparatus of  claim 33 , further comprising a power supply operatively connected to the at least two additional electrodes. 
     
     
         44 . The apparatus of  claim 43 , further comprising a controller operatively connected to the power supply and configured to regulate electrical potentials at the at least two electrodes. 
     
     
         45 . The apparatus of  claim 44 , further comprising a sensing electrode configured to provide feedback to the controller. 
     
     
         46 . The apparatus of  claim 45 , wherein the sensing electrode is located between the buffer reservoir and the gel medium. 
     
     
         47 . The apparatus of  claim 33 , further comprising a pump coupled to the buffer reservoir.