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.
The design and construction of mutual interaction models between artificial microsystems and living cells have the potential to open a wide range of novel applications in biomedical and biomimetic technologies. In this study, an artificial form of invasion‐defense mutual interactions is established in a community of glucose oxidase (GOx)‐containing liquid coacervate microdroplets and living cells, which interact via enzyme‐mediated reactive oxygen species (ROS) damage. The enzyme‐containing coacervate microdroplets, formed via liquid–liquid phase separation, act as invader protocells to electrostatically bind with the host HepG2 cell, resulting in assimilation. Subsequently, the glucose oxidation in the liquid coacervates initiates the generation of H2O2, which serves as an ROS resource to block cell proliferation. As a defense strategy, introduction of catalase (CAT) into the host cells is exploited to resist the ROS damage. CAT‐mediated decomposition of H2O2 leads to the ROS scavenging and results in the recovery of cell viability. The results obtained in the current study highlight the remarkable opportunities for the development of mutual interacting communities on the interface of artificial protocells/living cells. They also provide a new approach for engineering cellular behaviors through exploiting artificial nonliving microsystems.
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