Patent ID: 7992591
Filing Date: 2011-08-09
Classification: B01F,B01L,Y10T

Abstract:
1. An apparatus for mixing of microfluidic streams on a chip, said apparatus comprising: a micro-channel on said chip; and a plurality of magnetic valves on said chip; wherein a guiding magnet produces a proximal magnetic field gradient at a location of each of said plurality of magnetic valves when an operator places said guiding magnet in a vicinity of said chip; wherein a first magnetic valve of said plurality of magnetic valves controls fluid flow in said micro-channel; wherein each magnetic valve of said plurality of magnetic valves comprises a magnetic bead and a cavity on said chip next to a corresponding micro-channel section of said micro-channel; wherein said magnetic bead comprises: a magnetic volume element; wherein said magnetic volume element forces said magnetic bead to move along a cavity length of said cavity in response to said proximal magnetic field gradient, and a bead surface cover, wherein said bead surface cover provides chemical resistance and reduces friction and stiction of said magnetic bead within said cavity; wherein said cavity length is perpendicular to said corresponding micro-channel section, and said cavity length has a closed end away from said corresponding micro-channel section and an open end at said corresponding micro-channel section; wherein said open end is tapered so to prevent said magnetic bead from completely blocking said corresponding micro-channel section; wherein said each magnetic valve is at an on-state, if said magnetic bead is at said closed end of said cavity length allowing an unconstraint fluid flow through said corresponding micro-channel section; wherein said each magnetic valve is at a constricting-state, if said magnetic bead is at said open end of said cavity length and partially blocking fluid flow through said corresponding micro-channel section by narrowing a fluid path at said corresponding micro-channel section to enhance said mixing of microfluidic streams at said narrowed fluid path; wherein said vicinity of said chip comprises a plurality of guiding magnet position ranges; wherein said operator repositions guiding magnet within said plurality of guiding magnet position ranges in order to actuate said plurality of magnetic valves simultaneously; wherein if said guiding magnet is within a maximum mixing position range of said plurality of guiding magnet positions ranges, then each magnetic valve in said plurality of magnetic valves is simultaneously at said constricting-state; wherein if said guiding magnet is within a high mixing position range of said plurality of guiding magnet positions ranges, then simultaneously, each magnetic value in a first subset of said plurality of magnetic values is at said constricting-state, and each magnetic valve in a second subset of said plurality of magnetic valves is at said on-state, wherein each magnetic valve in said plurality of said magnetic valves is either in said first subset or in said second subset; wherein if said guiding magnet is within a low mixing position range of said plurality of guiding magnet positions ranges, then simultaneously, each magnetic value in said first subset is at said on-state, and each magnetic valve in said second subset is at said constricting-state; and wherein if said guiding magnet is within a minimum mixing position range of said plurality of guiding magnet positions ranges, then each magnetic valve in said plurality of magnetic valves is simultaneously at said on-state.