Enabling gradient biomineralization and prestress with a macroscopic matrix: the fish swim bladder for bioprocessing-inspired fabrication.

The hierarchical mineralization of bone inspires advanced materials, yet replicating it macroscopically remains challenging. The fish swim bladder (FSB) is a natural collagen scaffold that could bridge this gap. Its bone-like architecture guided gradient biomineralization and intrinsic prestress generation, yielding exceptional mechanical properties. The mineralized FSB enabled bioprocessing-inspired fabrication of high-performance bulk composites.