Mechanical stress soft/ hard discontinuities overcome for more durable soft robotics, exoskeletons, and bio-integrated medical implants

https://techxplore.com/news/2026-09-insect-approach-metals-tune-strength.html

"adds trace amounts of nickel, copper, or zinc ions to chitosan, a chitin derivative... programs precise high rigidity zones alongside soft, flexible regions within continuous sheet, mimicking insect exoskeletons' chitin structure alteration using metal-ion cross-linking... origami-inspired prototype folds/ unfolds without glues, seams, or separate mechanical components... seamless gradients within 1 underlying biopolymer, so can be composted/ recycled as single unit without tedious disassembly/ sorting"