Jump to main content
Jump to site search


A microfluidic platform integrating pressure-driven and electroosmotic-driven flow with inline filters for affinity separations

Author affiliations

Abstract

Pancreatic islets of Langerhans release glucagon to maintain blood glucose levels, and release of this peptide is dysregulated in diabetes mellitus. Although the importance of proper secretion of this peptide has been shown, no measurement of its release at the single islet level has been reported. In previous work, a non-competitive assay for glucagon was developed with a 6 pM limit of detection, low enough to measure from a single islet. To incorporate this method in an online assay, a microfluidic system with several distinct features was developed. To maintain appropriate flow rates in the presence of the high concentration of salt that was required for the assay, a piezo-actuated pressure transducer with inline flow sensors was used to drive sample flow through 80 × 50 μm (width × depth) channels, while electroosmotic flow was used to gate the sample away from a 15 × 5 μm separation channel. Flow rates tested in this system were 50–200 nL min−1 with relative standard deviations (RSDs) ranging from 1–4%. Use of the pressure-driven flow was found to increase the amount of clogs in the system, so a method to incorporate inline filters into the channels was developed. A total of 4 low resistance, inline microfabricated filters were evaluated, with all designs prolonging the operation time of the microfluidic device to more than 4 hours without clogs observed. Use of this system enabled highly reproducible injections (3–6% RSD). During initial incorporation of the non-competitive assay for glucagon, it was determined that Joule heating was problematic and temperature measurements revealed the separation channel increased to more than 50 °C during operation. A 3D-printed manifold was used to hold a Peltier cooler in place on the microfluidic device which produced a 2.6-fold improvement in the amount of the noncovalent glucagon complex that was detected compared to without cooling. These features are expected to be useful for not only long-term monitoring of the glucagon release from islets of Langerhans, but has the potential to be applied to a number of other microfluidic separation-based assays as well.

Graphical abstract: A microfluidic platform integrating pressure-driven and electroosmotic-driven flow with inline filters for affinity separations

Back to tab navigation

Supplementary files

Publication details

The article was received on 15 Aug 2019, accepted on 11 Oct 2019 and first published on 29 Oct 2019


Article type: Paper
DOI: 10.1039/C9AY01758E
Anal. Methods, 2019, Advance Article
  • Open access: Creative Commons BY-NC license
  •   Request permissions

    A microfluidic platform integrating pressure-driven and electroosmotic-driven flow with inline filters for affinity separations

    W. Leng, K. Evans and M. G. Roper, Anal. Methods, 2019, Advance Article , DOI: 10.1039/C9AY01758E

    This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material and it is not used for commercial purposes.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements