Continuous Flow Reactors from Microfluidic Compartmentalization of Enzymes within Inorganic Microparticles

Compartmentalisation and selective transport of molecular species are key aspects of chemical transformations inside the cell. In an artificial setting, the immobilisation of a wide range of enzymes onto surfaces is commonly used for controlling their functionality but such approaches can restrict their efficacy and expose them to degrading environmental conditions, thus reducing their activity. Here we employ an approach based on droplet microfluidics to generate enzyme-containing microparticles which feature an inorganic silica shell that forms a semi-permeable barrier. We show that this porous shell permits selective diffusion of the substrate and product while protecting the enzymes from degradation by proteinases and maintaining their functionality over multiple reaction cycles. We illustrate the power of this approach by synthesizing microparticles that can be employed to detect glucose levels through simultaneous encapsulation of two distinct enzymes that form a controlled reaction cascade. These results demonstrate a robust, accessible and modular approach for the formation of microparticles containing active but protected enzymes for molecular sensing applications and potential novel diagnostic platforms