Encapsulation of enzymes within porous materials has shown great promise for protecting enzymes from denaturation, increasing their tolerance to harsh environments and promoting their industrialization. However, controlling the conformational freedom of the encapsulated enzymes to enhance their catalytic performance remains a great challenge. To address this issue, herein, following immobilization of GOx and HRP on a thermo-responsive porous poly(styrene-maleic-anhydride-N-isopropylacrylamide) (PSMN) membrane, a GOx–HRP@PSMN@HZIF-8 composite was fabricated by encapsulating GOx–HRP@PSMN in hollow ZIF-8 (HZIF-8) with liposome (L) as the sacrificial template. The improved conformational freedom for enzymes arising from the hollow cavity formed in ZIF-8 through the removal of L enhanced the mass transfer and dramatically promoted the catalytic activity of the composite. Interestingly, at high temperature, the coiled PN moiety in PSMN provided the confinement effect for GOx–HRP, which also significantly boosted the catalytic performance of the composites. Compared to the maximum catalytic reaction rates (V_max) of GOx–HRP@PSMN@LZIF-8, the free enzyme and GOx–HRP@ZIF-8, the V_max of the GOx–HRP@PSMN@HZIF-8 composite exhibited an impressive 17.8-fold, 10.8-fold and 6.0-fold enhancement at 37 °C, respectively. The proposed composites successfully demonstrated their potential as catalytic platforms for the colorimetric detection of glucose in a cascade reaction. This study paves a new way for overcoming the current limitations of immobilizing enzymes in porous materials and the use of smart polymers for the potential fabrication of enzyme@polymer@MOF composites with tunable conformational freedom and confinement effect.

中文翻译：

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将酶固定的智能聚合物膜封装在金属有机框架中以增强催化性能

将酶封装在多孔材料中在保护酶免于变性、提高其对恶劣环境的耐受性和促进其工业化方面显示出巨大的前景。然而，控制封装酶的构象自由度以增强其催化性能仍然是一个巨大的挑战。为了解决这个问题，本文将 GOx 和 HRP 固定在热响应性多孔聚（苯乙烯-马来酸酐-N-异丙基丙烯酰胺）（PSMN）膜上后，通过以下方法制备了 GOx-HRP@PSMN@HZIF-8 复合材料：以脂质体（L）为牺牲模板，将 GOx–HRP@PSMN 封装在中空 ZIF-8（HZIF-8）中。通过去除 L，ZIF-8 中形成的中空腔提高了酶的构象自由度，增强了传质并显着提高了复合材料的催化活性。有趣的是，在高温下，PSMN中卷曲的PN部分为GOx-HRP提供了限制作用，这也显着提高了复合材料的催化性能。与GOx–HRP@PSMN@LZIF-8、游离酶和GOx–HRP@ZIF-8的最大催化反应速率（ V _max ）相比， GOx–HRP@PSMN@HZIF-8复合材料的V _max表现出在 37°C 下分别提高了 17.8 倍、10.8 倍和 6.0 倍，令人印象深刻。所提出的复合材料成功地证明了其作为级联反应中葡萄糖比色检测催化平台的潜力。这项研究为克服目前在多孔材料中固定酶的局限性以及使用智能聚合物潜在制造具有可调构象自由度和限制效应的酶@聚合物@MOF复合材料铺平了一条新途径。