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Microfluidic Polymer Valves

Sandia National Laboratories

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Check valve incorporating a mobile polymer <br />monolith into a multiple-level silica microchannel.
Check valve incorporating a mobile polymer
monolith into a multiple-level silica microchannel.

Schematic of laser-polymerization.
Schematic of laser-polymerization.

Technology Marketing SummaryIn a technological breakthrough, Sandia researchers have developed polymer microvalves to allow fluids to be shuttled as easily in microfluidic chips as they are on a laboratory benchtop. The valves are photopatterned, cast-to-shape microscale polymer elements that can be used to isolate electric fields, and, as a consequence, locally isolate electroosmotic or electrophoretic flows. The valves can be actuated by applying pressure to move them inside a microfluidic channel in order to open and close flow pathways, isolating and manipulating the fluids of interest.DescriptionSandia’s isolated cast-in-place microvalves feature the only architecture currently available that enables control of high-pressure (350 bar) fluid flow in microchannels, while simultaneously controlling high-voltage (1 kV). Sandia’s microfluidic polymer valves enable micro-scale systems to apply high-pressure techniques with a wide range of chemical solvents while retaining easy control of microfluidic pathways. These valves are chemically inert, preventing adsorption of species on the valve surface, and enabling low-friction valve motion.Benefits
  • Effectively control both electrokinetic and high-pressure hydraulic flow.
  • Greater process speeds using minuscule volumes of reagents, which saves money
  • Significantly rapid response time (in milliseconds).
  • Does not dissipate heat to the substrate
  • Multiple microvalves may be placed on a chip for about 5 cents in materials cost
  • Photopatterning the microvalves is rapid--only taking from 5 to 90 seconds.
  • Valves can be operated in harsh, aggressive solvents as well as typical analytical solvents (such as water, methanol, and acetonitrile).
  • No electrical power is dissipated into the fluid during valve operation.
  • The microvalve dielectric strength is comparable to glass.
  • Quantitative analysis is possible since common biochemical analytes neither react with nor adhere to valve surfaces.
Applications and Industries
  • Miniaturization of gradient liquid chromatography analysis
  • Chemical processing
  • Chemical reactions
  • Multi-dimensional separations
  • Detection of biological and chemical agents
  • Drug development
  • Detection of trace chemical impurities
  • Isolation, sorting, and manipulation of biological samples
Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Date
Patent 6,988,402
Patent
6,988,402
Mobile monolithic polymer elements for flow control in microfluidic devices
A cast-in-place and lithographically shaped mobile, monolithic polymer element for fluid flow control in microfluidic devices and method of manufacture. Microfluid flow control devices, or microvalves that provide for control of fluid or ionic current flow can be made incorporating a cast-in-place, mobile monolithic polymer element, disposed within a microchannel, and driven by fluid pressure (either liquid or gas) against a retaining or sealing surface. The polymer elements are made by the application of lithographic methods to monomer mixtures formulated in such a way that the polymer will not bond to microchannel walls. The polymer elements can seal against pressures greater than 5000 psi, and have a response time on the order of milliseconds. By the use of energetic radiation it is possible to depolymerize selected regions of the polymer element to form shapes that cannot be produced by conventional lithographic patterning and would be impossible to machine.
Sandia National Laboratories 01/24/2006
Issued
Patent 6,782,746
Patent
6,782,746
Mobile monolithic polymer elements for flow control in microfluidic devices
A cast-in-place and lithographically shaped mobile, monolithic polymer element for fluid flow control in microfluidic devices and method of manufacture. Microfluid flow control devices, or microvalves that provide for control of fluid or ionic current flow can be made incorporating a cast-in-place, mobile monolithic polymer element, disposed within a microchannel, and driven by either fluid or gas pressure against a retaining or sealing surface. The polymer elements are made by the application of lithographic methods to monomer mixtures formulated in such a way that the polymer will not bond to microchannel walls. The polymer elements can seal against pressures greater than 5000 psi, and have a response time on the order of milliseconds. By the use of energetic radiation it is possible to depolymerize selected regions of the polymer element to form shapes that cannot be produced by conventional lithographic patterning and would be impossible to machine.
Sandia National Laboratories 08/31/2004
Issued
Patent 6,952,962
Patent
6,952,962
Mobile monolithic polymer elements for flow control in microfluidic devices
A cast-in-place and lithographically shaped mobile, monolithic polymer element for fluid flow control in microfluidic devices and method of manufacture. Microfluid flow control devices, or microvalves that provide for control of fluid or ionic current flow can be made incorporating a cast-in-place, mobile monolithic polymer element, disposed within a microchannel, and driven by fluid pressure (either liquid or gas) against a retaining or sealing surface. The polymer elements are made by the application of lithographic methods to monomer mixtures formulated in such a way that the polymer will not bond to microchannel walls. The polymer elements can seal against pressures greater than 5000 psi, and have a response time on the order of milliseconds. By the use of energetic radiation it is possible to depolymerize selected regions of the polymer element to form shapes that cannot be produced by conventional lithographic patterning and would be impossible to machine.
Sandia National Laboratories 10/11/2005
Issued
Patent 7,022,381
Patent
7,022,381
Method for producing high dielectric strength microvalves
A microvalve having a cast-in-place and lithographically shaped mobile, polymer monolith for fluid flow control in microfluidic devices and method of manufacture. The microvalve contains a porous fluorinated polymer monolithic element whose pores are filled with an electrically insulating, high dielectric strength fluid, typically a perfluorinated liquid. This combination provides a microvalve that combines high dielectric strength with extremely low electrical conductivity. These microvalves have been shown to have resistivities of at least 100 G.OMEGA. and are compatible with solvents such as water at a pH between 2.7 and 9.0, 1-1 propanol, acetonitrile, and acetone.
Sandia National Laboratories 04/04/2006
Issued
Patent 6,865,939
Patent
6,865,939
Fluorinated silica microchannel surfaces
A method for surface modification of microchannels and capillaries. The method produces a chemically inert surface having a lowered surface free energy and improved frictional properties by attaching a fluorinated alkane group to the surface. The coating is produced by hydrolysis of a silane agent that is functionalized with either alkoxy or chloro ligands and an uncharged C.sub.3 -C.sub.10 fluorinated alkane chain. It has been found that the extent of surface coverage can be controlled by controlling the contact time from a minimum of about 2 minutes to a maximum of 120 minutes for complete surface coverage.
Sandia National Laboratories 03/15/2005
Issued
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
SD# 8386.0; SD# 8386.1; SD# 8298.0; SD# 8421.1; SD# 8392PrototypeAvailable09/29/201101/15/2013

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