Color-specific porosity in double pigmented natural 3d-nanoarchitectures of blue crab shell

Abstract3D-engineered nanoarchitectures with various functionalities are still difficult to obtain and translate for real-world applications. However, such nanomaterials are naturally abundant and yet wasted, but could trigger huge interest for blue bioeconomy, provided that our understanding of their ultrastructure-function is achieved. To date, the Bouligand pattern in crustaceans shell structure is believed to be unique. Here we demonstrated that in blue crab Callinectes sapidus, the 3D-nanoarchitecture is color-specific, while the blue and red-orange pigments interplay in different nano-sized channels and pores. Thinnest pores of about 20 nm are found in blue shell. Additionally, the blue pigment co-existence in specific Bouligand structure is proved for the green crab Carcinus aestuarii, although the crab does not appear blue. The pigments interplay, simultaneously detected in color-specific, native crab shells overturns our understanding in crustaceans coloration and may trigger the selective use of particular colored natural nanoarchitectures for biomolecular loading and slow release, infectious barriers, bioremediation, translational diffusivity and many others.