MONOLITHIC 3-D MICROFLUIDIC DEVICE FOR CELL ASSAY WITH AN INTEGRATED COMBINATORIAL MIXER

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MONOLITHIC 3-D MICROFLUIDIC DEVICE FOR CELL ASSAY
WITH AN INTEGRATED COMBINATORIAL MIXER
Mike C. Liu, Dean Ho, Yu-Chong Tai
Department of Bioengineering, California
Institute of Technology, Pasadena, USA
Department of Biomedical and Mechanical
Engineering, Northwestern University, Evanston,
USA
Department of Electrical Engineering, California
Institute of Technology, Pasadena, USA
Transducers07 pp.787-790
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Outline

• Introduction
• Device design and fabrication
• Experimental and discussion
• Conclusion

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Outline

• Introduction
• Device design and fabrication
• Experimental and discussion
• Conclusion

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Biological Assays Devices

• Drug screening and biological assays often
  include multiple combinations of different
  compounds.

Traditional screening tools
Microfluidic devices
robotics
multi-well plates
P. J. Lee, 2006
K. R. King,2007
Shane J. Stafslien, 2005
T. Chapman, 2003
Poor small-volume liquid handling ability Large
consumption of reagents High cost of operation
Inexpensive chip-platforms High-density
arrays Only expose cells to a single compound at
once
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3-D Microfluidic Combinatorial Mixer
Combinatorial Mixer
Individually chamber
LOC device
Streams control
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Outline

• Introduction
• Device design and fabrication
• Experimental and discussion
• Conclusion

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Design
Overpass Allow one microfluidic channel to
cross over other microfluidic channels
1 cm1 cm chip

• Combinatorial mixer
• Deliver different solution
• combinations to the
• culture-chambers

Three inputs seven possible outputs One control
channel
Cell culture-chambers Cells culture
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Device Fabrication
1.Si wafer clean H2SO4H2O2 31 Promote
adhesion DI waterIPAA-174 1001001
2.Parylene-coated Si 3µm Sacrificial
photoresist AZ4620 15µm Parylene 10µm
3.Pattern parylene oxygen plasma
4.Sacrificial photoresist AZ4620 32µm
Parylene 10µm
5.SU-8 100µm Elute AZ4620 IPA
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Packaging
Appliance
Transparent acrylic Milled with a
computer-numerical controlled (CNC) machine
PDMS layer 1. Gasket layer to provide proper
sealing 2. Adapter to connect the tubes 3.
Adjusted as open or blocked
Teflon tubes Plugged into the holes of the PDMS
layer
Programmable syringe pumps Controll the food
coloring solutions load and the flow rate
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Outline

• Introduction
• Device design and fabrication
• Experimental and discussion
• Conclusion

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Combinatorial Mixer Operated
flow rate 0.1L min-1
flow rate 10L min-1
D diffusion coefficient U fluid velocity w
channel width Z distance during time period
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Microfluidic Cell Culture
1.UV irradiation 70 ethanol solution PBS
solution 0.05 polyethyleneimine (PEI) 24h
2.B35 cells adhered to the culture-chamber 4 h
3.Continuous perfusion of culture media at
flow rate of 33 nL/min , 37C.
The cells were grown with continuous perfusion of
culture media and pictures were taken 4 h, 16 h
and 42 h after cells were loaded.
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Simple Cell Assay
1.B35 cells injected 4 h.
2.Injecting 3 cell stains crystal violet,
methylene blue, neutral red.
3.The combinatorial mixer
4.The various combinatorial streams into the cell
culture-chambers.
5.Cells were stained with different color patterns
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Conclusion

• The ability to simultaneously treat arrays of
  cells with different combinations of compounds.
• The fruition of such system will enable LOC
  devices to perform highly parallel and
  combinatorial chemical or biochemical reactions
  with reduced labors, reagents and time.
• The fabrication technology can enhance the
  functionalities of current LOC devices by
  integrating the devices with complex 3-D
  microfluidic networks.
• Future work
• Monitoring cell growth, more complicated
  cellular response
• Real-time monitoring of gene expression

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References

• Mike C. Liu , Dean Ho, Yu-Chong Tai, Monolithic
  fabrication of three-dimensional microfluidic
  networks for constructing cell culture array with
  an integrated combinatorial mixer, Sensors and
  Actuators B, 2007.
• P. J. Lee, P. J. Hung, V. M. Rao and L. P. Lee,
  Nanoliter scale microbioreactor array for
  quantitative cell biology, Biotechnology and
  Bioengineering, Vol. 94, No. 1, pp. 5-14, 2006.
• K. R. King, S. Wang, D. Irimia, A. Jayaraman, M.
  Toner and M. L. Yarmush, A high-throughput
  microfluidic real-time gene expression living
  cell array, Lab on a Chip, Vol. 7, pp. 77-85,
  2007.
• T. Chapman, Lab automation and robotics
  automation on the move, Nature 421 (2003) 661666.