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Submitted by Nishit Kumar Roll no 22, sectionA7802 Subject code BTY 001A

Date-23-02-09

Submitted to Dr. Nitaraj Sharma

Biominerals

A mollusc shell

Contents 1. Introduction of Biominerals 2. Formation of Biominerals 3. Functions of biominerals 4. Uses of Biominerals in industrial processes

Abstract: The well-organized multifunctional structures, systems and biogenic materials found in nature have attracted the interest of scientists working in many disciplines. The efforts have resulted in the biominerals which were only synthesized by nature only that is now being synthesized artificially also. In this article I present a small review of big area of Biominerals and explore how ideas from nature are being interpreted and modified to suit efforts aimed at designing better minerals and synthesizing newer materials.

Introduction of Biominerals Reverence for the beauty and usefulness of the naturally occurring materials around us has been felt and expressed ever since man learned to use them for improving the quality of life and standard of living. Various stages, in the growth of our civilization are therefore aptly named after stone, iron and bronze. It is customary to refer to the current millennium as the age of materials. Our nature is a continuous production unit of minerals. Nature uses very few materials to create bewildered variety of life forms and the mineral formed by the nature are called BIOMINERALS. Exact definition can be given by”Biomineralisation is the process by which living organism produce minerals often to harden or stiffen their existing tissues “I t is an extremely widespread phenomena in all five taxonomic kingdoms. The characteristics of biominerals are Self generating Hierarchical Multifunctional Self repairing Biodegradable These characteristics. The constitution and structure of the bone differs from animal to animal and even within the same animal from place to place in order to serve the specific needs.

Calcium Phosphates Biominerals are the bridges between the organic living and the nonliving mineral world. Living organisms form these crystalline minerals. Biominerals are materials such as bones, teeth etc. that perform important functions, and provide robust support and defense (mollusc shell, skeleton) to the individual. On this field pioneer research was done in1968 by Dr. De Arcy Thompson who published his research in the book “On growth and form”. Other researchers in this field are Frausto de Silva and Williams in 1991 and Mam et al in 1989. Organisms have been producing mineralized skeletons for the past 550million years. Other examples include copper, iron and gold deposits involving bacteria. Biologically-formed minerals often have special uses such as magnetic sensors in magneto tactic bacteria (Fe3O4), gravity sensing devices (CaCO3, CaSO4, BaSO4) and iron storage and mobilization (Fe2O3•H2O in the protein ferritin).

Sea shell

Structure and formation of biominerals Morphologic peculiarities of biominerals have remained a crystallographic paradox for decades. Although the permanent association of organic compounds with biologically produced minerals has been documented for a long time,no global concept was available until recent years, allowing us to explain the striking contrast between the morphologic diversity and astonishing specificity of biominerals among Invertebrate skeletons. Biominerals are formed by all living organisms, starting from bacteria to higher plants and animals. These minerals are formed in the matrix of bio-macromolecules like proteins, polysaccharides and lipids. Most biominerals are organized hierarchically and are ordered over many length scales starting from nano- to microscale. Biominerals are constituted from three basic parts 1. Organic part 2. Inorganic Crystals 3.Amorphous phase

Organic phase generally occupies very small fraction of total constructing phase. It ranges from hardening of existing tissues to synthesis of total constructing phase. It ranges hardening of existing tissues to synthesis of highly functional minerals. The inorganic part generally consists of crystals and aggregate of them arranged in well ordered array. growth modification on inorganic mineralization, provide useful insights into the possible mechanisms operating in nature. Since the proteins that have been found to be associated with biomineralization are usually highly acidic

macromolecules, simple water soluble chiral poly-carboxylate ligands were examined as models of biomineralization in aqueous solution. Biomineralisation involves the formation of these inorganic materials under the influence of proteins, carbohydrate and lipid. The formation of biominerals can be understood by the chart given below:

BIOMINERAL S Minerals which are produced biologically

Organic phase Hardening of existing tissues to synthesis of highly functional minerals

Inorganic Crystals Generally consist of crystals and aggregate of them arranged in well order array

Amorphous phase Phase containing growth factors

Functions of biominerals The formation of ferrihydrine core and its formation into haemosiderins is an example of Biomineralisation and the other is formation of magnetite from the magneto tactic bacteria. These biominerals bring hardness and stiffness in the body without which larger animals could not survive. Organic matrix consisting collagen, glycoproteins and polysaccharide brings elasticity and tensile strength. Therefore this is used as mechanically robust instrument and weapons. These are also used as sensor component by various organisms. There is a biominerals abundantly found in our body is calcium which is found as minerals form in our body.There are many other minerals there description is given below.

Chemical Composition

Mineral form

Function/ examples

Calcium carbonate CaCO3

Calcite Aragonite Vaterite Amorphous

Exoskeletons in corals, egg shells, mollusc shells Gravity sensor

Calcium phosphates Ca10(OH)2(PO4)6

hydroxyapaptite

Endoskeletons (human and other vertebrates bones and teeth

Calcium oxalate CaC2O4.nH2O

Whewellite weddelite

Calcium storage and defense of plants

Uses of biominerals in Industrial process

Most immediately striking aspect of biominerals is the range of truly exquisite and elaborate morphologies observed, which are frequently entirely disparate from their synthetic counterparts. Biominerals provide a unique inspiration for materials design, exhibiting unique and elaborate morphologies, and properties optimized for their function. For example, biominerals fulfilling structural roles typically possess remarkable mechanical properties which can rival those of engineering materials. For example, the skeletal elements of sea urchins comprise humble calcium carbonate, and yet fracture with difficulty, showing strength-to-weight ratios comparable, and even superior to many man-made construction materials. The mechanical properties of biominerals typically derive from their structural design and composite character. Sea urchin calcite occludes 0.1 wt% organic macromolecules which act as weak interfaces with the stiffer CaCO3 component deviating cracks along the cleavage planes, and therefore "protecting" the whole-structure against catastrophic fracture. The other highly arising aspect of minerals is cellulose fibers lignocellulosic agricultural byproducts are a copious and cheap source of these fibers. These agro based biofibers have the composition, properties and structure that make them suitable for uses such as composite textile, pulp and paper manufacture. In addition biofibers are also used to produce fuels, chemicals, enzyme and food.Biomimetics is the stream where research is going on to produce these minerals artificially.