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Issue 4, 2013
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Comprehensive integration of homogeneous bioassays via centrifugo-pneumatic cascading

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Abstract

This work for the first time presents the full integration and automation concept for a range of bioassays leveraged by cascading a centrifugo-pneumatic valving scheme to sequentially move several liquids through shared channel segments for multi-step sample preparation into the detection zone. This novel centrifugo-pneumatic liquid handling significantly simplifies system manufacture by obviating the need for complex surface functionalization procedures or hybrid material integration, as it is common in conventional valving methods such as capillary burst valves or sacrificial valves. Based on the centrifugo-pneumatic valving scheme, this work presents a toolkit of operational elements implementing liquid loading/transfer, metering, mixing and sedimentation in a microstructured polymer disc. As a proof of concept for the broad class of homogeneous bioassays, the full integration and automation of a colorimetric nitrate/nitrite test for the detection of clinically relevant nitric oxide (NO) in whole blood is implemented. First, 40 μL of plasma is extracted from a 100 μL sample of human blood, incubated for one hour with the enzymatic mixture (60 μL), and finally reacted with 100 μL of colorimetric (Greiss) reagents. Following just a single loading phase at the beginning of the process, all of these steps are automated through the centrifugo-pneumatic cascade with a high level of flow control and synchronization. Our system shows good correlation with controls up to 50 μM of nitrate, which adequately covers the healthy human range (4 to 45.3 μM).

Graphical abstract: Comprehensive integration of homogeneous bioassays via centrifugo-pneumatic cascading

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Publication details

The article was received on 27 Jun 2012, accepted on 26 Nov 2012 and first published on 28 Nov 2012


Article type: Paper
DOI: 10.1039/C2LC40722A
Citation: Lab Chip, 2013,13, 685-694
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    Comprehensive integration of homogeneous bioassays via centrifugo-pneumatic cascading

    N. Godino, R. Gorkin III, A. V. Linares, R. Burger and J. Ducrée, Lab Chip, 2013, 13, 685
    DOI: 10.1039/C2LC40722A

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