10/ Figure 1: www.nature.com/articles/nat...
Figure 2: www.researchgate.net/publication/...
Flea jump: journals.biologists.com/jeb/article/...

9/ Resilin exemplifies a class of functional biopolymers whose properties emerge from disorder and reversible confinement.
Its mechanics are instructive for designing sustainable, dynamic, and biocompatible materials.
Systems-level lessons from insects—applied at molecular scale!

8/ Open questions for material design:
• How does hydration modulate modulus and fatigue resistance?
• What crosslinking density optimizes recoil vs toughness?
• Can we co-assemble resilin-like domains with structured regions for hybrid behavior?

7/ Comparisons with structural proteins (e.g., silk, collagen) highlight a distinct design space:
Silk = strength via ordered β-sheets
Resilin = elasticity via disordered coils + sparse covalent locking

Different architectures, complementary functions.

6/ Synthetic analogs of resilin domains can be expressed recombinantly and crosslinked in vitro. That's what these fibers are!
This has enabled use in soft robotics, tissue scaffolds, and mechanical actuators.
Crosslinking remains enzyme-triggered, solvent-free, and modular.

5/ This crosslinked network:
• Lacks crystallinity
• Exhibits low hysteresis
• Functions across wide strain rates
• Operates in aqueous environments

Elasticity is entropic, not enthalpic—key to performance in dynamic biological systems.

4/ Uncrosslinked resilin is soluble.
Upon oxidative treatment (e.g. horseradish peroxidase + H₂O₂), tyrosine residues form dityrosine crosslinks.
This yields an amorphous, covalently linked network—mechanically robust but still hydrated and soft.

3/ Primary structure includes two key repeat motifs:
• Exon 1: GGRPSDSYGAPGGGN (x n)
• Exon 3: GYSGGRPGGQDLG (x n)
Both are glycine-rich, disordered, and highly flexible.
Minimal secondary structure → high conformational entropy → high recoil efficiency.

2/ Resilin is localized in high-strain regions: wing hinges, leg joints, tymbals.
It enables ultrafast motion by decoupling energy storage from direct muscular input—e.g., flea jumps, high-frequency wingbeats, or tymbal oscillation in cicadas.

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