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 bioad-hesive 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. Unex-pectedly, 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 in-terfacial accumulation, enhancing intermolecular{pi} -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.