Pickering Droplet-Derived Silica Microreactors with a Biomimetic Aqueous Environment for Continuous-Flow Enzymatic Reactions

Enhancing or restoring enzyme functions under cell-free conditions with good stability is typically difficult to achieve in traditional systems since the inherent conformation or structure of enzymes is highly dependent on their surroundings. Here, we describe the construction of silica microreactors with a biological-friendly aqueous environment for long-term continuous-flow enzymatic reactions. Based on a simple sol–gel growth process of the silica precursor around or within enzyme-containing Pickering droplets, biomimetic microreactors featuring an aqueous-filled-silica hybrid structure are successfully generated, which can not only ensure free enzymes with an intracellular analogous microenvironment but also significantly strengthen the operational stability against thermodynamic droplet coalescence. By packing these biomimetic microreactors into a fixed-bed reactor, continuous-flow enzymatic reactions are efficiently realized. As exemplified by the enzymatic hydrolysis kinetic resolution and transesterification reactions, this biomimetic microreactor-based continuous-flow system not only exhibited 2.57- and 4.36-fold enhancement in catalysis efficiency compared to batch experiments but also highlighted an impressive long-term durability over 700 h with negligible loss of catalytic activity. Moreover, the catalysis efficiency was demonstrated to be modulated through rationally engineering the microreactor dimensions or compactness, so that the catalytic reactions were controllable at a microscale level. This study offers exciting opportunities for building artificial microreactors with a biologically preferable environment for practical applications.