Nanotechnology: Principles and Practices

In his, very famous speech delivered in 1959, before the scientists of American Physical Society, Nobel Laureate Richard Feynman asked the scientists to derive the inspiration from Mother Nature to make the things smaller and see the advantages of making things smaller. Indeed the biological world, animal kingdom and plants make optimum use of materials and space. Nature indeed makes use of small spaces and corresponding confinement to synthesize inorganic materials or minerals abundantly found in earth’s crust. It uses insoluble, complex organic molecules as a reactor in which nucleation and growth of complex and hierarchical structures of inorganic materials takes place by reactions of organic soluble molecules. When we think of biological world, we normally think of delicate, temperature sensitive, carboneous or organic materials like leaves, roots, stems, cells, tissues and skin. Inorganic materials are also produced in biological systems. Bones, teeth, shells, nanomagnets inside the bodies of some bacteria and birds are some examples. Inorganic materials inside organic matter or organisms are known as biocomposites or biominerals. A variety of mechanically strong or weak, rigid or flexible, porous or nonporous, thick or thin materials either organic or inorganic in small or large quantities are abundantly produced in contact with live cells. These materials exhibit a wide variety in their functions like providing support to body, allow body movements and in general carry out various essential body functions.

The term ‘Self Assembly’ itself indicates its meaning. It is a gathering or collection of certain entities without any external influence. Although the term ‘self assembly’ has received a scientific acceptance over the last 3–4 decades and such assemblies are recognized in biology, chemistry or physics, some philosophers like Kanad, Democritus and Descarates several centuries back had imagined that everything in the world, from small objects around us to solar system, galaxies and universe is a result of tiny, non-divisible units (or atoms). The word ảtomos (Greek: ἄτομος) was first used by Democritus to mean uncuttable. Out of a chaotic situation, the various forms of matter get ordered following some laws of nature. Today we know that atoms can be further smashed with very high energy into still tinier particles viz. electrons, protons and neutrons. Protons and neutrons also are composed of fundamental particles like quarks. Yet, the concept that matter is composed of tiny units like atoms or molecules is still very useful for understanding most of the phenomena around us.