A minimalist design approach to simple coacervates from low-molecular-weight components

Coacervates are condensed, liquid-like assemblies formed through liquid–liquid phase separation via associative interactions among molecular components. Owing to their membraneless nature, coacervates exhibit unique dynamic features, such as coalescence and molecular sequestration, thus serving as promising platforms for drug delivery and the regulation of biological events. In this Focus Review, representative examples of simple coacervates composed of phase-separating low-molecular-weight molecules (LMWMs) are highlighted. This review provides a minimalist design strategy for LMWM-based simple coacervates based on surfactants and peptides and summarizes their unique functions, including stimulus-responsive structural transformations. The sophisticated design of these droplets is expected to enable a wide range of applications, including studies on the origins of life, the development of artificial cells, intracellular and in vivo protein delivery, biosensing, and molecular computing. Simple coacervates formed from low-molecular-weight molecules offer unique dynamic features, including stimulus-responsive phase transitions and reversible assembly/disassembly. This Focus Review highlights molecular design strategies, from historical perspectives to recent advancements. The sophisticated design of coacervates provides new opportunities in protocell models, biosensing, and drug delivery systems.