Microfluidic systems including three-dimensionally arrayed channel networks

• US 20080124663A1
• Filed: 11/08/2007
• Published: 05/29/2008
• Est. Priority Date: 05/25/2000
• Status: Abandoned Application

• Current Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Original Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Inventors: Whitesides, George M., Jackman, Rebecca J., McDonald, J. Cooper, Anderson, Janelle R., Chiu, Daniel T., Cherniavskaya, Oksana
• Application Number:
  US11/983,425
• Publication Number:
  US 20080124663A1
• Time in Patent Office: Days
• US Class Current: 430/324
• CPC Class Codes: B01D 2323/24 Use of template or surface directing agents [SDA]
• CPC Class Codes: B01D 2323/34 Use of radiation
• CPC Class Codes: B01D 2325/028 Microfluidic pore structures
• CPC Class Codes: B01D 2325/08 Patterned membranes
• CPC Class Codes: B01D 61/18 Apparatus therefor
• CPC Class Codes: B01D 67/003 by selective elimination of components, e.g. by leaching
• CPC Class Codes: B01D 67/0034 by micromachining techniques, e.g. using masking and etching steps, photolithography
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 71/70 Polymers having silicon in the main chain, with or without sulfur, nitrogen, oxygen or carbon only
• CPC Class Codes: B01D 71/701 Polydimethylsiloxane
• CPC Class Codes: B01L 2300/0874 Three dimensional network
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 3/502707 characterised by the manufacture of the container or its components by shaping or joining plastic parts B29C59/00, B29C65/00; by laminating B32B37/00; manufacture of microstructural devices in general B81C
• CPC Class Codes: B29C 2035/0827 using UV radiation
• CPC Class Codes: B29C 33/3857 by making impressions of one or more parts of models, e.g. shaped articles and including possible subsequent assembly of the parts
• CPC Class Codes: B29C 33/3892 Preparation of the model, e.g. by assembling parts
• CPC Class Codes: B29C 33/52 soluble or fusible in particular used in injection moulding B29C45/4457
• CPC Class Codes: B29C 35/0888 using transparant moulds
• CPC Class Codes: B29C 39/021 by casting in several steps
• CPC Class Codes: B29C 39/34 for undercut articles
• CPC Class Codes: B33Y 80/00 : Products made by additive manufacturing
• CPC Class Codes: B81B 2201/058 : Microfluidics not provided for in B81B2201/051 - B81B2201/054
• CPC Class Codes: B81C 1/00119 : Arrangement of basic structures like cavities or channels, e.g. suitable for microfluidic systems
• CPC Class Codes: B81C 2201/019 : Bonding or gluing multiple substrate layers
• CPC Class Codes: Y10T 436/11 : Automated chemical analysis
• CPC Class Codes: Y10T 436/2575 : Volumetric liquid transfer

Abstract

The present invention provides, in certain embodiments, improved microfluidic systems and methods for fabricating improved microfluidic systems, which contain one or more levels of microfluidic channels. The inventive methods can provide a convenient route to topologically complex and improved microfluidic systems. The microfluidic systems provided according to the invention can include three-dimensionally arrayed networks of fluid flow paths therein including channels that cross over or under other channels of the network without physical intersection at the points of cross over. The microfluidic networks of the invention can be fabricated via replica molding processes, also provided by the invention, utilizing mold masters including surfaces having topological features formed by photolithography. The microfluidic networks of the invention are, in some cases, comprised of a single replica molded layer, and, in other cases, are comprised of two, three, or more replica molded layers that have been assembled to form the overall microfluidic network structure. The present invention also describes various novel applications for using the microfluidic network structures provided by the invention.

Claims

1. A method for forming topological features on a surface of a material comprising:

exposing portions of surface of a first layer of photoresist to radiation in a first pattern;

coating the surface of the first layer of photoresist with a second layer of photoresist;

exposing portions of a surface of the second layer of photoresist to radiation in a second pattern different from the first pattern; and

developing the first and second photoresist layers with a developing agent to yield a positive relief pattern in photoresist, the positive relief pattern including at least one two-level topological feature having at least one cross-sectional dimension not exceeding about 500 μ

m, which two-level topological feature is characterized by a first portion having a first height with respect to the surface of the material and a second portion, integrally connected to the first portion, having a second height with respect to the surface of the material.