MPa . m 1/2 of fracture toughness), thanks to their microstructure . At the nanoscale, CaCO3 crystal grains form microscopic tiles 598 , blocking fracture propagation and enhancing material properties 599 . Organic bridges measuring 1-5 nm highlight the competitive feature size of self-organized biological materials 599 compared to photolithography's limits 600 . Self-microfabrication has the potential to improve existing achievements, and introduce innovative manufacturing methods 601 , such as pattern-driven materials self-assembly. Applications of this approach 602 promise biological materials combining sustainability with high mechanical performance 592 .