Hydrogel‐Immobilized Coacervate Droplets as Modular Microreactor Assemblies.

Immobilization of compartmentalized microscale objects in 3D hydrogels provides a step towards the modular assembly of soft functional materials with tunable architectures and distributed functionalities. Herein, we report the use of a combination of micro‐compartmentalization, immobilization, and modularization to fabricate and assemble hydrogel‐based microreactor assemblies comprising millions of functionalized polysaccharide–polynucleotide coacervate droplets. The heterogeneous hydrogels can be structurally fused by interfacial crosslinking and coupled as input and output modules to implement a UV‐induced photocatalytic/peroxidation nanoparticle/DNAzyme reaction cascade that generates a spatiotemporal fluorescence read‐out depending on the droplet number density, intensity of photoenergization, and chemical flux. Our approach offers a route to heterogeneous hydrogels with endogenous reactivity and reconfigurable architecture, and provides a step towards the development of soft modular materials with programmable functionality. [ABSTRACT FROM AUTHOR]