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Open AccessArticle

Hydrogel Microvalves as Control Elements for Parallelized Enzymatic Cascade Reactions in Microfluidics

1
Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
2
Organische Chemie der Polymere, Technische Universität Dresden, 01062 Dresden, Germany
3
Institut für Halbleiter- und Mikrosystemtechnik, Technische Universität Dresden, 01187 Dresden, Germany
*
Author to whom correspondence should be addressed.
Micromachines 2020, 11(2), 167; https://doi.org/10.3390/mi11020167
Received: 17 December 2019 / Revised: 26 January 2020 / Accepted: 1 February 2020 / Published: 5 February 2020
Compartmentalized microfluidic devices with immobilized catalysts are a valuable tool for overcoming the incompatibility challenge in (bio) catalytic cascade reactions and high-throughput screening of multiple reaction parameters. To achieve flow control in microfluidics, stimuli-responsive hydrogel microvalves were previously introduced. However, an application of this valve concept for the control of multistep reactions was not yet shown. To fill this gap, we show the integration of thermoresponsive poly(N-isopropylacrylamide) (PNiPAAm) microvalves (diameter: 500 and 600 µm) into PDMS-on-glass microfluidic devices for the control of parallelized enzyme-catalyzed cascade reactions. As a proof-of-principle, the biocatalysts glucose oxidase (GOx), horseradish peroxidase (HRP) and myoglobin (Myo) were immobilized in photopatterned hydrogel dot arrays (diameter of the dots: 350 µm, amount of enzymes: 0.13–2.3 µg) within three compartments of the device. Switching of the microvalves was achieved within 4 to 6 s and thereby the fluid pathway of the enzyme substrate solution (5 mmol/L) in the device was determined. Consequently, either the enzyme cascade reaction GOx-HRP or GOx-Myo was performed and continuously quantified by ultraviolet-visible (UV-Vis) spectroscopy. The functionality of the microvalves was shown in four hourly switching cycles and visualized by the path-dependent substrate conversion.
Keywords: thermoresponsive; hydrogel; valves; poly(N-isopropylacrylamide) (PNiPAAm); polydimethylsiloxane (PDMS)-on-glass; microfluidics; enzyme; parallelization thermoresponsive; hydrogel; valves; poly(N-isopropylacrylamide) (PNiPAAm); polydimethylsiloxane (PDMS)-on-glass; microfluidics; enzyme; parallelization
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MDPI and ACS Style

Obst, F.; Beck, A.; Bishayee, C.; Mehner, P.J.; Richter, A.; Voit, B.; Appelhans, D. Hydrogel Microvalves as Control Elements for Parallelized Enzymatic Cascade Reactions in Microfluidics. Micromachines 2020, 11, 167.

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