APPLICATIONS OF TECHNOLOGY:

• Concentrating, separating, mixing, and
  identifying compounds in systems involving:
  
  • microreactors
    
  • DNA sequencing and protein mapping
    
  • chromatography / electrochromatography
    
• Detection of chemical and biological warfare agents
  
• On-chip solid phase extraction (SPE)
  
• Environmental analysis and monitoring

ADVANTAGES:

• Enables construction of customized chips with zones of multiple functionalities and functions
  
• Only minute volumes of fluids are required
  
• More effective, versatile functional elements can be fabricated within channels
  
• Lower processing costs
  
• Devices are functional even at linear flow velocities of up to 50 mm/s
  
• Concentrates proteins extracted from a dilute solution by a factor of 1,000
  
• Very good mixing in devices as short as 5 mm

ABSTRACT:

Researchers at Berkeley Lab have invented concentration and mixing elements required to fabricate multi-functional analytical microfluidic systems. By including a variety of polymerized monoliths with different physical and chemical properties within the microchip channels, custom-made analytical systems can be constructed on a single chip.

The concentration and mixing elements invented by Jean Fréchet, Frantisek Svec, Cong Yu, and Thomas Rohr, are composed of porous polymer monoliths located within channels that are etched, embossed, or contoured in an inert substrate. The channels are filled with the polymerization mixture consisting of selected monomers, a free-radical initiator, and a porogenic solvent. The chip is then irradiated with UV light through a specifically designed mask. Photoinitiated polymerization occurs within exposed regions of the device and is prevented in areas blocked by the mask. This process is similar to photolithographic techniques used in the electronics industry.

Most current microfluidic devices feature open channel architecture. In contrast, fabricating the monolithic polymer within the channel significantly increases the available surface area and multiplies the number of desired interactions. Combining these monolithic elements on a chip will enable the preparation of tailor-made systems for detection and characterization of microorganisms, proteins, viruses, and small molecules.

The Berkeley Lab devices can be operated at flow velocities substantially exceeding those of typical state-of-the-art analytical microfluidic chips. For example, very good mixing has been achieved even at a high flow velocity of 36 mm/min in a monolithic static mixer only 5 mm long. Similarly, the enrichment of proteins extracted from a dilute solution exceeds 1,000 times using the simple monolithic concentrator having a volume of only 28 nL.

A large number of various monolithic materials differing in both porosity and chemistry can be prepared in situ via a combination of techniques including UV initiated polymerization, grafting, and post-modification. The availability of such materials and functional building blocks undoubtedly adds much to the limited array of materials and chemistries available today for analytical microfluidic chip technology, while also reducing the complexity and the manufacturing costs of the microchips.

STATUS: U.S. Patent #6,887,384. Available for licensing

REFERENCE NUMBER: IB-1739

FOR ADDITIONAL INFORMATION SEE:

Yu C., Davey M.H., Svec F., Frechet J.M., “Monolithic Porous Polymer for On-Chip Solid-Phase Extraction and Preconcentration Prepared by Photoinitiated In Situ Polymerization within a Microfluidic Device,” Analytical Chemistry 2001, 73, 5088-96.

Rohr T., Yu C., Davey M.H., Svec F., Frechet J.M., “Porous Polymer Monoliths: Simple and Efficient Mixers Prepared by Direct Polymerization in the Channels of Microfluidic Chips,” Electrophoresis 2001, 22, 3959-67

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