Toward a better understanding of mineral microstructure in bony tissues

Abstract

Bone is a multifunctional composite of type-I collagen fibrils and mineral crystallites organized into a complex hierarchical structure. Microstructural features of the mineral constituents in selected bony tissues, including bovine femur and armadillo and turtle osteoderms were characterized by optical and scanning electron microscopy before and after complete deproteinization. Minerals in the three types of bony tissues retained structural integrity after completely removing protein constituents and showed similar structural features at the nanoscale. High-resolution scanning electron microscopic images showed minerals formed fibril-like structures, aligned in a coherent manner along the orientation of collagen fibrils with a 67-nm periodicity. Organized porous structures at varying hierarchical levels were well preserved after complete deproteinization. The authors demonstrate that bone architecture, from the nano-to macro-scale can be better visualized and analyzed after deproteinization. A bony tissue with unique microstructure is reported for the armadillo osteoderm. This comparative study provides better understanding of the structure of the mineral constituents in bony tissues that could further lead to novel design of bioinspired composites.

Editorial

“…The first contribution from Po-Yu Chen et al 1 reports on the microstructural features of the mineral constituents in selected bony tissues including bovine femur, armadillo and turtle osteoderms. They used high-resolution imaging to study the composite and the mineral moiety after removing the proteinaceous content.…”

A Study of Perturbations in Structure and Elastic Modulus of Bone Microconstituents Using Bimodal Amplitude Modulated-Frequency Modulated Atomic Force Microscopy

“…Typically, the organic phase consists of biomacromolecules (type I collagen and noncollagenous proteins) while the inorganic phase mainly consists of hydroxyapatite (HA) crystals . As a result of the complex hierarchical structures consisting of both biomacromolecules and minerals with certain porosity, bone is stiff and tough in general. − Bone constituent analysis is normally divided into four size scales: nanoscale (measured in nanometers), submicroscale (one to tens of microns), microscale (tens to hundreds of microns) and mesoscale (hundreds of microns to millimeters or more) . Nanoscale analysis demonstrates that Type I collagen occupies 90% of the organic phase in bone .…”

Spines of the porcupine fish: Structure, composition, and mechanical properties

“…(a) Sea urchin [1], (b) lionfish [2], (c) stingray [3], (d) porcupine [4], (e) echidna [5], (f) cactus [6], (g) scorpion [7], and (h) honey bee [8]. Cross-sections of various spine structures found in nature: (a) hedgehog spine [17], (b) Old World porcupine quill [21], (c) sea urchin spine [1], (d) honey bee sting [8], (e) paper wasp sting [8], (f) scorpion sting [7], (g) cactus spine [19], (h) New World porcupine quill [23]. This thesis explores the structure, composition, and mechanical properties of the porcupine fish spine for the first time.…”

“…Hedgehogs use their quills to not only deter predators, but also to absorb energy when they fall from high places [17]. [21], (c) sea urchin spine [1], (d) honey bee sting [8], (e) paper wasp sting [8], (f) scorpion sting [7], (g) cactus spine [19], (h) New World porcupine quill [23].…”