Microfluidic magnetophoretic device and methods for using the same

Abstract

A microfluidic device may employ one or more sorting stations for separating target species from other species in a sample. The separation is driven by magnetophoresis. A sorting station generally includes separate buffer and sample streams. A magnetic field gradient applied to the sorting station deflects the flow path of magnetic particles (which selectively label the target species) from a sample stream into a buffer stream. The buffer stream leaving the sorting station is used to detect or further process purified target species labeled with the magnetic particles.

1 .- 45 . (canceled) 
     
     
         46 . A fluidic sorting device comprising:
 (a) a sample inlet channel configured to provide a sample stream comprising a target species, non-target species, and magnetic particles having an affinity for only the target species or non-target species in the sample;   (b) a buffer inlet channel configured to provide a buffer stream;   (c) a sorting station fluidically coupled to said sample inlet channel and to said buffer inlet channel and located in a path of the sample stream and the buffer stream;   (d) a magnetic field gradient generator for interacting with an external magnetic field to produce a magnetic field gradient in the sorting station and thereby trap the magnetic particles in the sorting station, wherein the magnetic field gradient generator comprises a ferromagnetic structure arranged to contact the buffer stream but not the sample stream during trapping, and wherein the sorting station is configured such that the only forces substantially affecting separation of the particles are hydrodynamic drag and attractive magnetophoretic forces; and   (e) an outlet channel.   
     
     
         47 . The fluidic sorting device of  claim 46 , wherein the magnetic field gradient generator is configured to capture magnetic particles at the magnetic field gradient generator. 
     
     
         48 . The fluidic sorting device of  claim 46 , wherein the magnetic field gradient generator is located within the sorting station. 
     
     
         49 . The fluidic sorting device of  claim 46 , wherein the magnetic field gradient generator is affixed to a wall of the sorting station at a location where it can contact the buffer stream during sorting. 
     
     
         50 . The fluidic sorting device of  claim 46 , wherein the device is configured such that the sample stream and the buffer stream flow on top of one another within the sorting region. 
     
     
         51 . The fluidic sorting device of  claim 50 , further comprising a separator structure defining the terminus of separate conduits for the buffer and sample streams and configured to provide a stacked parallel flow of the buffer and sample streams. 
     
     
         52 . The fluidic sorting device of  claim 46 , wherein the sorting station is configured to provide a stacked arrangement of the magnetic field gradient generator, the sample stream, and the buffer stream sandwiched between the magnetic field gradient generator and the sample stream during sorting. 
     
     
         53 . The fluidic sorting device of  claim 46 , wherein the magnetic field gradient generator comprises a micropatterned ferromagnetic structure. 
     
     
         54 . The fluidic sorting device of  claim 46 , further comprising a magnet proximate the magnetic field gradient generator. 
     
     
         55 . The fluidic sorting device of  claim 46 , further comprising a disruption station located downstream from the sorting station. 
     
     
         56 . A fluidic sorting device comprising:
 (a) a sample inlet channel configured to provide a sample stream comprising a target species, non-target species, and magnetic particles having an affinity for only the target species or non-target species in the sample;   (b) a buffer inlet channel configured to provide a buffer stream;   (c) a sorting station fluidically coupled to said sample inlet channel and to said buffer inlet channel and located in a path of the sample stream and the buffer stream, the sorting station comprising a separator structure defining the terminus of separate conduits for the buffer and sample streams and configured to provide a stacked parallel flow of the buffer and sample streams; and   (d) an outlet channel fluidically coupled to the sorting station,   wherein the sorting station is configured to trap at least some of the magnetic particles when exposed to a magnetic field, and provide a stacked arrangement of an external source of the magnetic field, the sample stream, and the buffer stream sandwiched between the magnetic field and the sample stream during sorting.   
     
     
         57 . The fluidic sorting device of  claim 56 , wherein the sorting station comprises a trapping surface proximate the external source of the magnetic field during sorting. 
     
     
         58 . The fluidic sorting device of  claim 57 , further comprising a magnetic field gradient generator on or in the trapping surface. 
     
     
         59 . The fluidic sorting device of  claim 58 , wherein the magnetic field gradient generator is configured to capture magnetic particles at the magnetic field gradient generator. 
     
     
         60 . The fluidic sorting device of  claim 58 , wherein the magnetic field gradient generator comprises a micropatterned ferromagnetic structure. 
     
     
         61 . The fluidic sorting device of  claim 58 , wherein the sorting station is configured to provide a stacked arrangement of the magnetic field gradient generator, the sample stream, and the buffer stream sandwiched between the magnetic field gradient generator and the sample stream during sorting. 
     
     
         62 . The fluidic sorting device of  claim 56 , wherein the only forces substantially affecting trapping of the magnetic particles are hydrodynamic drag and attractive magnetophoretic forces. 
     
     
         63 . The fluidic sorting device of  claim 56 , wherein the device is configured such that the sample stream and the buffer stream flow on top of one another within the sorting region. 
     
     
         64 . A fluidic sorting device comprising:
 (a) a sample inlet channel configured to provide a sample stream comprising a target species, non-target species, and magnetic particles having an affinity for only the target species or non-target species in the sample;   (b) a buffer inlet channel configured to provide a buffer stream;   (c) a sorting station fluidically coupled to said sample inlet channel and to said buffer inlet channel and located in a path of the sample stream and the buffer stream, the sorting station comprising a separator structure defining the terminus of separate conduits for the buffer and sample streams and configured to provide a stacked parallel flow of the buffer and sample streams; and   (d) an outlet channel fluidically coupled to the sorting station, and   wherein the only forces substantially affecting separation of the particles are hydrodynamic drag and attractive magnetophoretic forces.   
     
     
         65 . The fluidic sorting device of  claim 64 , further comprising a magnetic field gradient generator arranged to contact the buffer stream but not the sample stream. 
     
     
         66 . The fluidic sorting device of  claim 65 , wherein the magnetic field gradient generator is configured to capture magnetic particles at the magnetic field gradient generator. 
     
     
         67 . The fluidic sorting device of  claim 65 , wherein the magnetic field gradient generator comprises a micropatterned ferromagnetic structure. 
     
     
         68 . The fluidic sorting device of  claim 65 , wherein the sorting station is configured to provide a stacked arrangement of the magnetic field gradient generator, the sample stream, and the buffer stream sandwiched between the magnetic field gradient generator and the sample stream during sorting. 
     
     
         69 . The fluidic sorting device of  claim 64 , wherein the sorting station comprises a trapping surface proximate an external source of the attractive magnetophoretic forces during sorting. 
     
     
         70 . The fluidic sorting device of  claim 64 , wherein the device is configured such that the sample stream and the buffer stream flow on top of one another within the sorting region.