Technological watch

Rational protein engineering yields silk?amyloid?mussel hybrid fibers with exceptional tensile strength (401 MPa) and toughness (124 MJ/m3), yet full recyclability via rapid aqueous dissolution. Crystalline domains maintain load?bearing performance, while amorphous domains control solvent ingress. They address a fundamental trade?off in sustainable materials design and enable reprocessing into high?performance hydrogels with strong underwater adhesion.ABSTRACTDissolution recycling represents a promising and potentially cost?effective strategy for material regeneration and greenhouse gas reduction. Yet, very few polymers are practically recyclable by dissolution because strong intermolecular interactions, essential for mechanical performance, are typically incompatible with solvent disruption during dissolution. Here, we present a rational material engineering approach that balances these competing requirements to create high?performance, dissolution?recyclable protein?based materials (PBMs). Using protein engineering and synthetic biology, we designed silk?amyloid?mussel (SAM) protein hybrids whose amorphous domains control solvent ingress, while crystalline domains maintain load?bearing intermolecular interactions. The engineered SAM fibers, SAMHY, exhibited exceptional tensile strength (401 ± 40 MPa), toughness (124 ± 38 MJ/m?3), and minimal supercontraction (2.2% ± 1.9%) under high humidity (>90%), alongside full recyclability through a rapid (