Abstract

Material based classification of the different ages of human civilization, namely stone, wood, iron, bronze and now silicon, clearly highlights the appreciation for role of materials in the growth of human civilization over time. With time, the manifestation of human intellect leading to industrialization of the society, could take primitive materials from implements to implants, making the present millennium as the age of materials. A rapid growth of Materials Science & Technology could be attributed to (i) availabilty of advance analytical tools capable of looking deep into structure and property of materials, and (ii) an integration of physical sciences with biological sciences. The combined effect of above two approaches has made it possible for the scientists to reveal secrets of mother nature involved in the synthesis of multifunctional materials and structures through a time tested sustainable process under ambient conditions. It has been exciting to note that nature works on the principle of maximum from minimum and thus involving most abundant raw materials and minimum energy and creating almost no waste. Looking at the structures and composition of biologically produced functional materials, it has been confirmed that all of them are hybrid composites of organic and inorganic phases, having a hierarchical self assembly of nano sized building blocks, assembled together by secondary forces. Mother nature uses its composite materials for constructing and systematically running its entire kingdom comprising different types of living structures. Materials and structures produced by nature being nanocomposites exhibit remarkably controlled organic-inorganic interfaces, uniformity in the dimensions and morphology of inorganic crystals precipitated in organic matrix and their highly controlled crystallographic orientation with respect to matrix and the hierarchical self assembly of nanostructures, creating a ordered microstructures and ultimately a three dimensional macrostructure. Length scales involved in the self assembly induces multifunctional properties in such structures ranging from self generation, adaptation, sensing to self heeling. A human bone is among the best example of biologically produced nanocomposite structure, which is now treated as best working model to design futuristic load bearing structures having in-built property of self healing.