Chemico-mechanical microvalve and devices comprising the same

Abstract

Micro-fluid devices and methods for their use are provided. The subject devices are characterized by the presence of at least one micro-valve comprising a phase reversible material, e.g. a reversible gel, that reversibly changes its physical state in response to an applied stimulus, e.g. a thermoreversible gel. In using the subject device, fluid flow along a flow path of the device is modulated by applying an appropriate stimulus, e.g. changing the temperature, to the microvalve. The subject devices find use in a variety of applications, including micro-analytical applications.

What is claimed is:  
     
         1 . A micro-fluidic device having a fluid flow path and at least one micro-valve comprising a phase reversible material.  
     
     
         2 . The micro-fluidic device according to  claim 1 , wherein said device comprises two intersecting flow paths, wherein one of said flow paths is substantially filled with said phase reversible material and said micro-valve is positioned at the intersection of said intersecting flow paths.  
     
     
         3 . The micro-fluidic device according to  claim 1 , wherein said micro-valve comprises said phase reversible material stably associated with a high surface area component.  
     
     
         4 . The micro-fluidic device according to  claim 3 , wherein said high surface area component is stably associated with at least one wall of said fluid flow path.  
     
     
         5 . The micro-fluidic device according to  claim 3 , wherein said high surface area component is maintained in said flow path by a retaining means.  
     
     
         6 . The micro-fluidic device according to  claim 1 , wherein said phase reversible material is a phase reversible polymer.  
     
     
         7 . The micro-fluidic device according to  claim 1 , wherein said micro-valve modulates the rate of the fluid flow along said flow path.  
     
     
         8 . The micro-fluidic device according to  claim 1 , wherein said phase reversible material is thermo-reversible.  
     
     
         9 . A micro-fluidic device comprising a micro-valve and two intersecting flow paths, wherein one of said intersecting flow paths is substantially filled with a phase reversible material and said micro-valve is positioned at the intersection of said intersecting flow paths.  
     
     
         10 . The micro-fluidic device according to  claim 9 , wherein said micro-fluidic device comprises at least one micro-compartment.  
     
     
         11 . The micro-fluidic device according to  claim 10 , wherein said micro-compartment is a micro-channel.  
     
     
         12 . The micro-fluidic device according to  claim 9 , wherein said phase reversible material is a phase reversible polymer.  
     
     
         13 . The micro-fluidic device according to  claim 12 , wherein said phase reversible polymer is an N-isopropylacrylamide copolymer.  
     
     
         14 . The micro-fluidic device according to  claim 12 , wherein said phase reversible polymer is a polyalkylene oxide.  
     
     
         15 . The micro-fluidic device according to  claim 9 , wherein said micro-valve modulates the rate of the fluid flow along said flow path.  
     
     
         16 . The micro-fluidic device according to  claim 9 , wherein said phase reversible material is thermo-reversible.  
     
     
         17 . A micro-fluidic device comprising a fluid flow path and at least one micro-valve, wherein said micro-valve comprises a phase reversible material stably associated with a high surface area component, and wherein said high surface area component is stably associated with at least one surface of said flow path.  
     
     
         18 . The micro-fluidic device according to  claim 17 , wherein said high surface area component comprises an array of posts bonded to said at least one surface of said flow path.  
     
     
         19 . The micro-fluidic device according to  claim 17 , wherein said micro-fluidic device comprises at least one micro-compartment.  
     
     
         20 . The micro-fluidic device according to  claim 19 , wherein said micro-compartment is a micro-channel.  
     
     
         21 . The micro-fluidic device according to  claim 17 , wherein said phase reversible material is a phase reversible polymer.  
     
     
         22 . The micro-fluidic device according to  claim 21 , wherein said phase reversible polymer is an N-isopropylacrylamide copolymer.  
     
     
         23 . The micro-fluidic device according to  claim 21 , wherein said phase reversible polymer is a polyalkylene oxide.  
     
     
         24 . The micro-fluidic device according to  claim 17 , wherein said micro-valve modulates the rate of the fluid flow along said flow path.  
     
     
         25 . The micro-fluidic device according to  claim 17 , wherein said phase reversible material is thermo-reversible.  
     
     
         26 . A micro-fluidic device comprising a fluid flow path and at least one micro-valve, wherein said micro-valve comprises a phase reversible material stably associated with a high surface area component maintained in said flow path by a retaining means.  
     
     
         27 . The micro-fluidic device according to  claim 26 , wherein said retaining means comprises fluid permeable barriers positioned in said flow path on opposite sides of said high surface area component.  
     
     
         28 . The micro-fluidic device according to  claim 26 , wherein said retaining means comprises constrictions in said flow path present on either side of said high surface area component.  
     
     
         29 . The micro-fluidic device according to  claim 26 , wherein said high surface area component is selected from the group consisting of: a plurality of solid phase particles; a membrane; and a mesh structure.  
     
     
         30 . The micro-fluidic device according to  claim 26 , wherein said micro-fluidic device comprises at least one micro-compartment.  
     
     
         31 . The micro-fluidic device according to  claim 30 , wherein said micro-compartment is a micro-channel.  
     
     
         32 . The micro-fluidic device according to  claim 26 , wherein said phase reversible material is a phase reversible polymer.  
     
     
         33 . The micro-fluidic device according to  claim 32 , wherein said phase reversible polymer is an N-isopropylacrylamide copolymer.  
     
     
         34 . The micro-fluidic device according to  claim 32 , wherein said phase reversible polymer is a polyalkylene oxide.  
     
     
         35 . The micro-fluidic device according to  claim 26 , wherein said micro-valve modulates the rate of the fluid flow along said flow path.  
     
     
         36 . The micro-fluidic device according to  claim 26 , wherein said phase reversible material is thermo-reversible.  
     
     
         37 . A method of modulating fluid flow along a flow path of a micro-fluidic device, said method comprising: 
 modulating the physical state of a micro-valve positioned in said flow path, wherein said micro-valve comprises a phase reversible material.    
     
     
         38 . The method according to  claim 37 , wherein said phase reversible material is a phase reversible polymer.  
     
     
         39 . The method according to  claim 38 , wherein said phase reversible polymer is a thermoreversible polymer.  
     
     
         40 . The method according to  claim 37 , wherein said modulating comprises changing the temperature of said thermoreversible polymer.  
     
     
         41 . The method according to  claim 37 , wherein said modulating occurs by actuation of a phase reversing means.  
     
     
         42 . The method according to  claim 41 , wherein said phase reversing means is completely external to said device.  
     
     
         43 . The method according to  claim 41 , wherein at least one component of said phase reversing means is internal to said device.  
     
     
         44 . A kit for use in a fluid flow process, said kit comprising: 
 a micro-fluidic device according to  claim 1 .    
     
     
         45 . The kit according to  claim 44 , wherein said kit further comprises a phase reversing means.