Bacteria separation system and methods

Abstract

Methods and apparatus for detecting, quantifying, enriching, and/or separating bacterial species in fluid sample are provided. The fluid sample is provided as input to a microfluidic passage of a microfluidic device, wherein the microfluidic device comprises at least one electrode disposed adjacent to the microfluidic passage. The at least one electrode is activated to capture bacteria in the sample using dielectrophoresis, wherein the capture efficiency of bacteria is at least 99%.

1 - 64 . (canceled) 
     
     
         65 . A method of separating a first bacterial species and second bacterial species in a sample including at least the first bacterial species, the second bacterial species and other components, the method comprising:
 providing, as input to a microfluidic passage of a microfluidic chip, the sample, wherein the microfluidic passage has a first electrode system disposed adjacent to a first portion of the microfluidic passage and a second electrode system disposed adjacent to a second portion of the microfluidic passage;   generating, by at least one signal generator electrically connected to the first electrode system and the second electrode system, a first AC voltage to drive the first electrode system to produce a first electric field having first characteristics within the first portion of the microfluidic passage; and   generating by the at least one signal generator, a second AC voltage to drive the second electrode system to produce a second electric field having second characteristics within the second portion of the microfluidic passage,   wherein the first characteristics are different than the second characteristics,   wherein the first characteristics are selected such that the first electric field exerts a positive dielectrophoresis force on the first bacterial species sufficient to capture the first bacterial species on at least one first electrode in the first electrode system without capturing the second bacterial species or the other components in the sample, and   wherein the second characteristics are selected such that the second electric field exerts a positive dielectrophoresis force on the second bacterial species sufficient to capture the second bacterial species on at least one second electrode in the second electrode system without capturing the other components in the sample.   
     
     
         66 . The method of  claim 65 , wherein a frequency of the second AC voltage is higher than a frequency of the first AC voltage. 
     
     
         67 . The method of  claim 65 , wherein the other components include a third bacterial species, and wherein the microfluidic chip further includes a third electrode system disposed adjacent to a third portion of the microfluidic passage, the method further comprising:
 generating by the at least one signal generator, a third AC voltage to drive the third electrode system to produce a third electric field having third characteristics within the third portion of the microfluidic passage, wherein the third characteristics are selected such that the third electric field exerts a positive dielectrophoresis force on the third bacterial species sufficient to capture the third bacterial species on at least one third electrode in the third electrode system without capturing components of the other components other than the third bacterial species.   
     
     
         68 . The method of  claim 67 , wherein a frequency of the second AC voltage is higher than a frequency of the first AC voltage. 
     
     
         69 . The method of  claim 68 , wherein a frequency of the third AC voltage is higher than the frequency of second AC voltage. 
     
     
         70 . The method of  claim 65 , further comprising:
 capturing one or more first images of the at least one first electrode during capture of the first bacterial species;   capturing one or more second images of the at least one second electrode during capture of the second bacterial species; and   processing, by at least one computer, the one or more first images to quantify an amount of bacteria of the first bacterial species captured by the at least one first electrode and/or processing the one or more second images to quantify an amount of bacteria of the second bacterial species captured by the at least one second electrode.   
     
     
         71 . The method of  claim 65 , further comprising:
 generating by the at least one signal generator, following capture of the first bacterial species, a third AC voltage to drive the first electrode system to produce a third electric field having third characteristics within the first portion of the microfluidic passage,   wherein the third characteristics are selected such that the third electric field exerts a negative dielectrophoresis force on the captured first bacterial species sufficient to release the captured first bacterial species from the at least one first electrode in the first electrode system.   
     
     
         72 . The method of  claim 71 , further comprising:
 generating by the at least one signal generator, following capture of the second bacterial species, a fourth AC voltage to drive the second electrode system to produce a fourth electric field having fourth characteristics within the second portion of the microfluidic passage,   wherein the fourth characteristics are selected such that the fourth electric field exerts a negative dielectrophoresis force on the captured second bacterial species sufficient to release the captured second bacterial species from the at least one second electrode in the second electrode system.   
     
     
         73 . The method of  claim 65 , further comprising pumping the sample from an inlet of the microfluidic passage, past the first electrode system and second electrode system, and to an outlet of the microfluidic passage. 
     
     
         74 . The method of  claim 73 , wherein the pumping is performed with at least one pump disposed outside of a flow path of the sample. 
     
     
         75 . The method of  claim 73 , wherein the pumping is performed with at least one pump disposed between an outlet of the microfluidic passage and the first and second electrode systems. 
     
     
         76 . The method of  claim 65 , wherein each of the first and second electrode systems comprise an electrode comprising a plurality of concentric arcs. 
     
     
         77 . The method of  claim 76 , wherein the plurality of concentric arcs of the respective electrodes of the first and second electrode systems are spaced equally from each other. 
     
     
         78 . The method of  claim 65 , wherein each of the first and second electrode systems comprise a plurality of electrodes. 
     
     
         79 . The method of  claim 78 , wherein the plurality of electrodes of each of the first and second electrode systems are arranged along at least two dimensions of the microfluidic passage. 
     
     
         80 . The method of  claim 79 , wherein the plurality of electrodes of each of the first and second electrode systems are arranged along three dimensions of the microfluidic passage.