Microfluidic Fabrication of Hydrogel Microparticles with MOF-Armoured Multi-Enzymes for Cascade Biocatalytic Reactions

Uniform hydrogel microparticles with MOF nanoparticles for molecular co-confinement of cascade enzymes are developed by droplet microfluidics to achieve enhanced stability and reusability under harsh conditions. Water-swollen polyacrylamide hydrogel is used for constructing the microparticles; while microporous zeolitic imidazolate framework-8 (ZIF-8) nanoparticles are incorporated in the hydrogel networks for multi-enzyme co-confinement. With the ZIF-8 nanoparticles as armour, the multiple enzymes in the microparticles show good stability for efficient biocatalytic cascades under harsh conditions. This is demonstrated by using glucose oxidase (GOx) and horseradish peroxidase (HRP) as typical cascade enzymes. The hydrogel microparticles with both GOx and HRP confined in their ZIF-8 nanoparticles exhibit enhanced stability for efficient biocatalytic cascades and storage, after treatment under harsh conditions involving high temperature, UV light, and protease. Moreover, the hydrogel microparticles allow easy recycling and good reusability after repeated treatment at high temperature (80 °C). This work provides a simple and efficient strategy to create multiple-enzyme-loaded microcarriers with good stability and reusability for biocatalytic cascades.