Obst Franziska, Beck Anthony, Bishayee Chayan, Mehner Philipp J, Richter Andreas, Voit Brigitte, Appelhans Dietmar
Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany.
Organische Chemie der Polymere, Technische Universität Dresden, 01062 Dresden, Germany.
Micromachines (Basel). 2020 Feb 5;11(2):167. doi: 10.3390/mi11020167.
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(-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.
带有固定化催化剂的分隔式微流控装置是克服（生物）催化级联反应中不相容挑战以及高通量筛选多个反应参数的宝贵工具。为了实现微流控中的流量控制，之前引入了刺激响应水凝胶微阀。然而，尚未展示这种阀概念在多步反应控制中的应用。为了填补这一空白，我们展示了将热响应性聚（N-异丙基丙烯酰胺）（PNiPAAm）微阀（直径：500和600 µm）集成到玻璃上PDMS微流控装置中，以控制并行的酶催化级联反应。作为原理验证，生物催化剂葡萄糖氧化酶（GOx）、辣根过氧化物酶（HRP）和肌红蛋白（Myo）被固定在装置三个隔室中的光图案化水凝胶点阵列（点的直径：350 µm，酶量：0.13 - 2.3 µg）中。微阀在4至6秒内实现切换，从而确定了装置中酶底物溶液（5 mmol/L）的流体路径。因此，进行了酶级联反应GOx - HRP或GOx - Myo，并通过紫外可见（UV - Vis）光谱进行连续定量。微阀的功能在四个每小时的切换循环中得到展示，并通过与路径相关的底物转化率进行可视化。
