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Biomedical Microdevices

, Volume 9, Issue 6, pp 795–799 | Cite as

Single-step centrifugal hematocrit determination on a 10-$ processing device

  • L. Riegger
  • M. Grumann
  • J. Steigert
  • S. Lutz
  • C. P. Steinert
  • C. Mueller
  • J. Viertel
  • O. Prucker
  • J. Rühe
  • R. Zengerle
  • J. Ducrée
Article

Abstract

We present a novel concept to process human blood on a spinning polymer disk for the determination of the hematocrit level by simple visual inspection. The microfluidic disk which is spun by a macroscopic drive unit features an upstream metering structure and a downstream blind channel where the centrifugally enforced sedimentation of the blood is performed. The bubble-free priming of the blind channel is governed by centrifugally assisted capillary filling along the sloped hydrophilic side-wall and the lid as well as the special shape of the dead end of the two-layer channel. The hematocrit is indicated at the sharp phase boundary between the plasma and the segregated cellular pellet on a disk-imprinted calibrated scale. This way, we conduct the hematocrit determination of human blood within 5 min at a high degree of linearity (R 2 = 0.999) and at a high accuracy (CV = 4.7%) spanning over the physiological to pathological working range. As all processing steps including the priming, the metering to a defined volume as well as the centrifugation are executed automatically during rotation, the concept is successfully demonstrated in a conventional PC-CDROM drive while delivering the same performance (R 2 = 0.999, CV = 4.3%).

Keywords

Bubble-free priming Hematocrit All-in-one CDROM Centrifugal microfluidics 

Notes

Acknowledgement

The authors are grateful to the partial financial support by the German federal state of Baden-Württemberg (contract number 24-720.431-1-7/2).

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Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • L. Riegger
    • 1
  • M. Grumann
    • 1
  • J. Steigert
    • 1
  • S. Lutz
    • 1
  • C. P. Steinert
    • 1
  • C. Mueller
    • 2
  • J. Viertel
    • 3
  • O. Prucker
    • 3
  • J. Rühe
    • 3
  • R. Zengerle
    • 1
    • 4
  • J. Ducrée
    • 1
    • 4
  1. 1.Laboratory for MEMS Applications, Department of Microsystems Engineering (IMTEK)University of FreiburgFreiburgGermany
  2. 2.Laboratory for Process Technology, IMTEKUniversity of FreiburgFreiburgGermany
  3. 3.Laboratory for Chemistry and Physics of Interfaces, IMTEKUniversity of FreiburgFreiburgGermany
  4. 4.HSG-IMIT—Institute for Micromachining and Information TechnologyFreiburgGermany

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