Light-Triggered Coacervation of Low-Molecular-Weight Amphiphiles for Tunable Chemical Reactivity

Coacervate droplets formed via liquid–liquid phase separation (LLPS) are promising dynamic microenvironments for regulating biochemical reactions. However, most artificial coacervates rely on polymeric components, limiting their responsiveness and tunability. Here, we report a light-responsive, low-molecular-weight coacervate system constructed from azobenzene-based cationic amphiphiles (AzoN) and anionic surfactants (SDBS). Upon UV irradiation, trans–cis photoisomerization of AzoN altered molecular packing, inducing a phase transition from vesicles and birefringent assemblies into isotropic coacervate droplets. These droplets selectively sequestered enzymes and substrates, leading to an enhancement of enzymatic activity at specific compositions. While fully reversible control of reactivity was not demonstrated, the formation of light-gated reaction compartments showcases a strategy to dynamically modulate chemical environments via supramolecular architecture reorganization. This study offers a minimalistic approach toward stimuli-responsive chemical systems based on low-molecular-weight building blocks, with potential applications in synthetic biology and adaptive materials science.