Manganese and calcium reinforced claws spiders

German and Israeli bioengineers to study the relationship between structure, composition and mechanical properties of the claws of the spider Cupiennius salei and came to the conclusion that the ions of manganese and calcium locally strengthen their fields due to cross-stitching the binding proteins of the cuticle. In terms of resistance to abrasion of the claws of the spider overtake a organic biological structure and are flush with enamel and mother of pearl. Work published in the journal Advanced Functional Materials.

Claws, fangs and stings of animals for a long time improved for a more successful piercing of the victim, cutting her tissue and grip. They, like many other natural structures are built from small set of materials: polysaccharides like chitin and cellulose, proteins such as keratin, collagen and fibroin, and minerals (carbonate and phosphate of calcium and silica). Despite this, mechanical properties of biomaterials is extensive, mainly due to the heterogeneity of the composition and hierarchical architecture.

An example of such a material can serve as the cuticle of arthropods. Spiders she lies in the basis of the claws on the legs and chelicerae. The claws help them to walk, climb, and cling to rough surfaces. And with the help of the chelicerae animal pierces the exoskeleton of the victim and injects his poison. Cuticle composed of filamentous procuticula and external epicuticle. They chitin-protein fibers are formed either in layers with a parallel direction of the strands or twisted plywood structure, in which the direction of the chitin crystals changes from layer to layer.

This variability of the fiber structure leads to significant changes in the mechanical properties of the cuticle in different parts of the body of an animal. Moreover, the spiders Cupiennius salei chelicerae locally hardened due to the cross-stitching histidinemia sites protein zinc ions. The processes of mineralization are more common in crustaceans, and other arthropods accumulate zinc ions, manganese and calcium in cuticular adaptations (for example, insect stings, jaws and iceclad). The mechanical behaviour of the cuticle was studied largely, but large-scale analysis of the relationship between structure, properties and functions was carried out. Such an analysis would establish the mechanism of adaptation to special functions at the material level.

Tadayon Mariam (Maryam Tadayon) and Yael also held the role Politi (Yael Politi) with colleagues from Institute for colloids and surfaces of the max Planck Society and the University named after Ben-Gurion simulated mechanical stress on the claws Cupiennius salei and determined how different parts of the cuticle structure adapts to the loads, and then compared the adapted structure of the chelicerae and claws of the spider with other biological objects.

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