▪ Abstract The term bone refers to a family of materials, all of which are built up of mineralized collagen fibrils. They have highly complex structures, described in terms of up to 7 hierarchical levels of organization. These materials have evolved to fulfill a variety of mechanical functions, for which the structures are presumably fine-tuned. Matching structure to function is a challenge. Here we review the structure-mechanical relations at each of the hierarchical levels of organization, highlighting wherever possible both underlying strategies and gaps in our knowledge. The insights gained from the study of these fascinating materials are not only important biologically, but may well provide novel ideas that can be applied to the design of synthetic materials.

THE MATERIAL BONE: Structure-Mechanical Function Relations

Otolith microstructure examination has found an increasing number of applications in recent years. However, few workers have critically assessed the assumptions upon which the age and growth infere...

Microstructure of Fish Otoliths

Calcium oxalate (CaOx) crystals are distributed among all taxonomic levels of photosynthetic organisms from small algae to angiosperms and giant gymnosperms. Accumulation of crystals by these organisms can be substantial. Major functions of CaOx crystal formation in plants include high-capacity calcium (Ca) regulation and protection against herbivory. Ultrastructural and developmental analyses have demonstrated that this biomineralization process is not a simple random physical-chemical precipitation of endogenously synthesized oxalic acid and environmentally derived Ca. Instead, crystals are formed in specific shapes and sizes. Genetic regulation of CaOx formation is indicated by constancy of crystal morphology within species, cell specialization, and the remarkable coordination of crystal growth and cell expansion. Using a variety of approaches, researchers have begun to unravel the exquisite control mechanisms exerted by cells specialized for CaOx formation that include the machinery for uptake and accumulation of Ca, oxalic acid biosynthetic pathways, and regulation of crystal growth.

CALCIUM OXALATE IN PLANTS: Formation and Function

“Biomineralization links soft organic tissues, which are compositionally akin to the atmosphere and oceans, with the hard materials of the solid Earth. It provides organisms with skeletons and shells while they are alive, and when they die these are deposited as sediment in environments from river plains to the deep ocean floor. It is also these hard, resistant products of life which are mainly responsible for the Earth’s fossil record. Consequently, biomineralization involves biologists, chemists, and geologists in interdisciplinary studies at one of the interfaces between Earth and life.” (Leadbeater and Riding 1986) 

Biomineralization refers to the processes by which organisms form minerals. The control exerted by many organisms over mineral formation distinguishes these processes from abiotic mineralization. The latter was the primary focus of earth scientists over the last century, but the emergence of biogeochemistry and the urgency of understanding the past and future evolution of the Earth are moving biological mineralization to the forefront of various fields of science, including the earth sciences.

The growth in biogeochemistry has led to a number of new exciting research areas where the distinctions between the biological, chemical, and earth sciences disciplines melt away. Of the wonderful topics that are receiving renewed attention, the study of biomineral formation is perhaps the most fascinating. Truly at the interface of earth and life, biomineralization is a discipline that is certain to see major advancements as a new generation of scientists brings cross-disciplinary training and new experimental and computational methods to the most daunting problems. It is, however, by no means a new field. The first book on biomineralization was published in 1924 in German by W.J. Schmidt (Schmidt 1924), and the subject has continued to intrigue a dedicated community of scientists for many years. Until the early 1980s the field was known as …

/pdf/an-overview-of-biomineralization-processes-and-the-problem-4pmi251r4p.pdf

An Overview of Biomineralization Processes and the Problem of the Vital Effect

The present overview is intended to point the readers’ attention to the important subject of calcium orthophosphates. These materials are of the special significance because they represent the inorganic part of major normal (bones, teeth and dear antlers) and pathological ( i.e. those appearing due to various diseases) calcified tissues of mammals. Due to a great chemical similarity with the biological calcified tissues, many calcium orthophosphates possess remarkable biocompatibility and bioactivity. Materials scientists use this property extensively to construct artificial bone grafts that are either entirely made of or only surface-coated with the biologically relevant calcium ortho-phosphates. For example, self-setting hydraulic cements made of calcium orthophosphates are helpful in bone repair, while titanium substitutes covered by a surface layer of calcium orthophosphates are used for hip joint endoprostheses and as tooth substitutes. Porous scaffolds made of calcium orthophosphates are very promising tools for tissue engineering applications. In addition, technical grade calcium orthophosphates are very popular mineral fertilizers. Thus ere calcium orthophosphates are of great significance for humankind and, in this paper, an overview on the current knowledge on this subject is provided.

https://www.mdpi.com/1996-1944/2/2/399/pdf

Calcium Orthophosphates in Nature, Biology and Medicine

Periostracum Formation and Shell Regeneration in the Lingulid Glottidia pyramidata (Brachiopoda: Inarticulata)

Uptake and transport of shell minerals in Glottidia pyramidata Stimpson (Brachiopoda: Inarticulata)

Shell growth of Glottidia pyramidata Stimpson (Brachiopoda : Inarticulata)

Studies on the biology of fish bone—II bone matrix changes during resorption

Histopathological studies on the cirripede crustacean,Balanus eburneus, at light and electron microscopic levels indicated that the chitin-inhibiting insecticide, diflubenzuron, caused similar disruption of the exoskeleton as observed in insects. Under the light microscope, globular particles were present within the chitinous layers of the cuticle, and these particles appeared electron dense and pleomorphic at the ultrastructural level. The cytoplasm of the cuticle-secreting epidermal cells appeared more dense and showed at least a five-fold increase in multivesicular bodies, which possessed electron dense cores. Barnacles exposed to diflubenzuron for 10 days or longer at 750 and 1,000 ppb were delayed in the premolt phase of cuticle secretion.

Norimitsu Watabe

Papers

Periostracum Formation and Shell Regeneration in the Lingulid Glottidia pyramidata (Brachiopoda: Inarticulata)

Uptake and transport of shell minerals in Glottidia pyramidata Stimpson (Brachiopoda: Inarticulata)

Shell growth of Glottidia pyramidata Stimpson (Brachiopoda : Inarticulata)

Studies on the biology of fish bone—II bone matrix changes during resorption

Histopathological effects of diflubenzuron on the cirripede crustacean, Balanus eburneus.