Analytical and Bioanalytical Chemistry

, Volume 398, Issue 5, pp 1985–1991 | Cite as

Microfluidic multi-analyte gradient generator

  • Liaoran Cao
  • Xinyu Zhang
  • Alix Grimley
  • Anna R. Lomasney
  • Michael G. RoperEmail author
Original Paper


A microfluidic device was developed to produce temporal concentration gradients of multiple analytes. Four on-chip pumps delivered pulses of three analytes and buffer to a 14-cm channel where the pulses were mixed to homogeneity. The final concentration of each analyte was dependent on the temporal density of the pulses from each pump. The concentration of each analyte was varied by changing the number of pump cycles from each reservoir while maintaining the total number of pump cycles per unit time to ensure a constant total flow rate in the device. To gauge the independent nature of each pump, sinusoidal waves of fluorescein concentration were produced from each pump with independent frequencies and amplitudes. The resulting fluorescence intensity was compared with a theoretical summation of the waves and the experimental data matched the theoretical waves within 1%, indicating that the pumps were operating independently and outputting the correct frequency and amplitude. The device was used to demonstrate the role of adenosine triphosphate-sensitive K+ channels in glucose-stimulated increases in intracellular [Ca2+] in islets of Langerhans. Perfusion of single islets of Langerhans with combinations of glucose, diazoxide, and K+ resulted in intracellular Ca2+ patterns similar to what has been observed using conventional perfusion devices. The system will be useful in other studies with islets of Langerhans, as well as other assays that require the modulation of multiple analytes in time.


Microfluidic Gradient Pumping Perfusion Multi-analyte 



This work was funded in part by grants from the National Institutes of Health (R01 DK080714) and the American Heart Association Greater Southeast affiliate.


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Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Liaoran Cao
    • 1
  • Xinyu Zhang
    • 1
  • Alix Grimley
    • 1
  • Anna R. Lomasney
    • 1
  • Michael G. Roper
    • 1
    Email author
  1. 1.Department of Chemistry and BiochemistryFlorida State UniversityTallahasseeUSA

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