Metal-encoded droplet longevity enables catalytic microenvironments and drives emergent adhesive properties

Liquid-liquid phase separation (LLPS) drives the formation of biomolecular condensates that regulate intracellular processes. Beyond proteins and nucleic acids, short peptides also form protocell-like droplets that recapitulate primitive compartmentalization and catalytic microenvironments, while also offering emergent soft-matter functionality. Yet controlling their lifetimes and linking phase behavior to emergent material and catalytic properties remain unexplored.

We provide a facile strategy to prolong droplet lifetimes through metal-ligand coordination in a minimalistic synthon inspired by the stickers-and-spacers framework of intrinsically disordered proteins. The resulting droplets were comprehensively characterized using multiple complementary techniques, including optical microscopy, CLSM, cryo-SEM, dynamic light scattering (DLS), and fluorescence recovery after photobleaching (FRAP).

These droplets serve as catalytic crucibles, in which the confined microenvironment enhances local reactant concentration and lowers the reaction barrier, thereby boosting product formation. Over time, the droplets undergo structural maturation into fibers, reminiscent of protein condensates that evolve into ordered aggregates, demonstrating how complex behavior can emerge from simple building blocks. The persistence of metal-aided droplet-like intermediates not only caused uniform nucleation before the liquid-solid transition, resulting in dense fibrous networks with enhanced rigidity and ductility, but also maximized interfacial contact and intimate wetting before solidification, thereby ensuring robust adhesion, particularly in a small-molecular system. This work demonstrates how a rudimentary system can form protocell-like droplets and how metal-ligand coordination modulates LLPS dynamics, offering a facile route to engineer catalytic and materials attributes within biomimetic platforms.