Microparticles made from stimuli-responsive materials are promising structures for controlled release, adsorption materials, and sensors. We envision them also to mimic autonomous muscle-like contraction and expansion cycles. This requires a combination of reaction-induced volume switching and switchable substrate supply. For this purpose, we report the synthesis of enzymatic active, monodisperse, porous, and pH-responsive microspheres. The microspheres were synthesized by utilizing a versatile flow chemistry device combining droplet formation, UV-initiated free radical polymerization, and superimposed phase separation between the polymer and a water–methanol mixture. Uptake experiments revealed the switchable permeability for glucose. This switchable permeability adjusts the enzymatic conversion rate of glucose by changing the microparticles swelling state. The developed synthetic and fluidic framework will allow rendering the microparticle diameter and porosity as well as the conversion rates. Balancing these rates adequately may enable autonomous contraction and expansion cycles of such microparticles.

中文翻译：

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具有pH响应性和反应性的单分散多孔微球

由刺激响应材料制成的微粒是用于控释，吸附材料和传感器的有前途的结构。我们设想他们还模仿自主肌肉样的收缩和扩张周期。这需要将反应引发的体积切换和可切换的基板供应结合在一起。为此，我们报告了酶促活性，单分散，多孔和pH响应性微球的合成。微球是通过利用一种通用的流动化学装置合成的，该装置结合了液滴的形成，紫外线引发的自由基聚合以及聚合物与水-甲醇混合物之间的叠加相分离。摄取实验揭示了葡萄糖的可切换渗透性。该可切换的渗透性通过改变微粒的溶胀状态来调节葡萄糖的酶促转化率。发达的合成和流体框架将允许呈现微粒的直径和孔隙率以及转化率。适当地平衡这些速率可以使这些微粒能够自主地收缩和膨胀。