Biomedical Microdevices

, Volume 9, Issue 2, pp 123–134

Quantitative measurement and control of oxygen levels in microfluidic poly(dimethylsiloxane) bioreactors during cell culture

  • Geeta Mehta
  • Khamir Mehta
  • Dhruv Sud
  • Jonathan W. Song
  • Tommaso Bersano-Begey
  • Nobuyuki Futai
  • Yun Seok Heo
  • Mary-Ann Mycek
  • Jennifer J. Linderman
  • Shuichi Takayama
Article

DOI: 10.1007/s10544-006-9005-7

Cite this article as:
Mehta, G., Mehta, K., Sud, D. et al. Biomed Microdevices (2007) 9: 123. doi:10.1007/s10544-006-9005-7

Abstract

Microfluidic bioreactors fabricated from highly gas-permeable poly(dimethylsiloxane) (PDMS) materials have been observed, somewhat unexpectedly, to give rise to heterogeneous long term responses along the length of a perfused mammalian cell culture channel, reminiscent of physiologic tissue zonation that arises at least in part due to oxygen gradients. To develop a more quantitative understanding and enable better control of the physical-chemical mechanisms underlying cell biological events in such PDMS reactors, dissolved oxygen concentrations in the channel system were quantified in real time using fluorescence intensity and lifetime imaging of an oxygen sensitive dye, ruthenium tris(2,2’-dipyridyl) dichloride hexahydrate (RTDP). The data indicate that despite oxygen diffusion through PDMS, uptake of oxygen by cells inside the perfused PDMS microchannels induces an axial oxygen concentration gradient, with lower levels recorded in downstream regions. The oxygen concentration gradient generated by a balance of cellular uptake, convective transport by media flow, and permeation through PDMS in our devices ranged from 0.0003 (mg/l)/mm to 0.7 (mg/l)/mm. The existence of such steep gradients induced by cellular uptake can have important biological consequences. Results are consistent with our mathematical model and give insight into the conditions under which flux of oxygen through PDMS into the microchannels will or will not contribute significantly to oxygen delivery to cells and also provide a design tool to manipulate and control oxygen for cell culture and device engineering. The combination of computerized microfluidics, in situ oxygen sensing, and mathematical models opens new windows for microphysiologic studies utilizing oxygen gradients and low oxygen tensions.

Keywords

Oxygen sensing PDMS Microbioreactor Microfluidics Fluorescence intensity Fluorescence lifetime imaging microscopy (FLIM) Oxygen gradients Myoblast Ruthenium tris(2,2’-dipyridyl) dichloride hexahydrate (RTDP) 

Supplementary material

10544_2006_9005_Figa_ESM.jpg (36 kb)
Fig. S1

Braille pump (gray) and valve (valves down, white) positions during fibronectin adsorption

10544_2006_9005_Figb_ESM.jpg (39 kb)
Fig. S2

Flow direction (solid green arrows) and valve (valve-up: gray with black border, valve-down: white) positions during cell seeding

Copyright information

© Springer Science+Business Media, LLC 2006

Authors and Affiliations

  • Geeta Mehta
    • 1
  • Khamir Mehta
    • 2
  • Dhruv Sud
    • 1
  • Jonathan W. Song
    • 1
  • Tommaso Bersano-Begey
    • 1
  • Nobuyuki Futai
    • 1
  • Yun Seok Heo
    • 1
  • Mary-Ann Mycek
    • 1
    • 4
    • 5
  • Jennifer J. Linderman
    • 1
    • 2
  • Shuichi Takayama
    • 1
    • 3
  1. 1.Department of Biomedical EngineeringUniversity of MichiganAnn ArborUSA
  2. 2.Department of Chemical EngineeringUniversity of MichiganAnn ArborUSA
  3. 3.Macromolecular Science and EngineeringUniversity of MichiganAnn ArborUSA
  4. 4.Applied Physics ProgramUniversity of MichiganAnn ArborUSA
  5. 5.Comprehensive Cancer CenterUniversity of MichiganAnn ArborUSA

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