Abdon Pena-Francesch1
University of Michigan1
Squids have developed predatory teethed structures in their suction cups that are composed of structural proteins. Unlike other hard tissue in cephalopods, these biological materials are stabilized by β-sheet nanocrystalline structures that give rise to high-strength materials without mineralization. Here, we introduce cephalopod-inspired polypeptides with a repetitive diblock design (alanine-rich and glycine-rich blocks) that self-assemble into β-sheet nanocrystalline structures. These β-sheet nanocrystals act as physical and reversible hydrogen-bonded crosslinks in supramolecular protein networks, where β-sheet size and network topology regulate the physical properties. We demonstrate the dynamic properties of squid-inspired polypeptides in self-healing networks with healing strength and kinetics (~25 MPa strength after 1 second of healing) surpassing those typically found in other natural and synthetic soft polymers. This family of proteins and their biosynthetic derivatives open new opportunities in bioinspired design for adaptive functional materials, and we demonstrate their potential in actuator prototypes for applications in soft robotics and wearable technology.