Smart Hydrogel Doped by Metal-Organic Frameworks for Renewable Self-Pumping Enzymatic Reactors.

The construction of high-performance immobilized enzymes is vastly desired for green biotransformation. Although hydrogels offer significant potential for facilitating biomedical applications of enzymes due to their flexibility, macroscopic processability, and extracellular matrix-like properties. However, maintaining enzymatic activity and recyclability within bulk hydrogels remains a formidable challenge due to restricted passive mass transfer and enzyme leakage. Herein, inspired by the heart's blood-pumping mechanism, a smart metal-organic framework (MOFs)-doped hydrogel is developed for enzyme immobilization to effectively address these challenges. Importantly, thermally triggered contraction/expansion cycles of the hydrogel, coupled with a dynamic water stream, significantly enhance substrates intake and endogenous products expulsion, while enzymes are effectively retained due to the interception effect of MOFs. This activity can be tuned by adjusting hydrogel contractility, enabling active mass transfer and regeneration similar to living tissues. Benefit from these advantages, the biosystems perform well in biosensing applications. This study provides a novel solution for enzymatic immobilization in porous 3D matrices and opens opportunities for the construction of life-like bio-microdevices or artificial organelles.