Condensate-based shells and scaffolds via interfacial liquid-to-solid transition of disordered peptides

Living organisms use biomolecular condensates to respond to dynamic environments and create functional materials with complex architectures. Exploring such phase-separated systems beyond the naturally occurring scenarios may offer valuable insights for emergent synthetic biosystems. Here, we report the self-assembly behavior of a short, disordered peptide sequence (termed CT45) derived from a protein present in the bioadhesive system of tick ectoparasites. We show that CT45 spontaneously accumulates at polar-nonpolar interfaces, and further undergoes liquid-liquid and liquid-to-solid phase transitions to create mechanically stable structures. When encapsulated within vesicles and presented with a stable oil-water interface, CT45 rapidly forms solid shells, which can be reinforced by up-concentrating the material through osmotic imbalance. Unexpectedly, when presented with a transient acetone-water interface, CT45 condenses at the evaporating interface and forms interconnected, porous mesoscopic scaffolds. The underlying mechanism is found to be the amphiphilic nature of CT45 leading to interfacial accumulation, enhancing intermolecular π-based interactions to trigger phase transitions. The micron-sized shells exhibit appreciable mechanical strength and the porous scaffolds present a highly stable platform capable of retaining molecules. In conclusion, the presented condensate-based microscopic and mesoscopic scaffolds hold significance in customizable condensate architectures, with potential applications in biomedical engineering and synthetic biology.