Nature has gone through evolution over the 3.8 Gyr since life is estimated to have appeared on Earth. Nature has evolved objects with high performance using commonly found materials. These function on the macroscale to the nanoscale. The understanding of the functions provided by objects and processes found in nature can guide us to imitate and produce nanomaterials, nanodevices and processes. Biologically inspired design or adaptation or derivation from nature is referred to as ‘biomimetics’. It means mimicking biology or nature. Biomimetics is derived from the Greek word biomimesis. The word was coined by polymath Otto Schmitt in 1957, who, in his doctoral research, developed a physical device that mimicked the electrical action of a nerve. Other words used include bionics (coined in 1960 by Jack Steele of Wright-Patterson Air Force Base in Dayton, OH), biomimicry and biognosis. The field of biomimetics is highly interdisciplinary. It involves the understanding of biological functions, structures and principles of various objects found in nature by biologists, physicists, chemists and material scientists, and the design and fabrication of various materials and devices of commercial interest by engineers, material scientists, chemists and others. The word biomimetics first appeared in Webster's dictionary in 1974 and is defined as ‘the study of the formation, structure or function of biologically produced substances and materials (as enzymes or silk) and biological mechanisms and processes (as protein synthesis or photosynthesis) especially for the purpose of synthesizing similar products by artificial mechanisms which mimic natural ones’.
Biological materials are highly organized from the molecular to the nanoscale, microscale and macroscale, often in a hierarchical manner with intricate nanoarchitecture that ultimately makes up a myriad of different functional elements. Nature uses commonly found materials. Properties of the materials and surfaces result from a complex interplay between the surface structure and the morphology and physical and chemical properties. Many materials, surfaces and devices provide multifunctionality. Molecular-scale devices, superhydrophobicity, self-cleaning, drag reduction in fluid flow, energy conversion and conservation, reversible adhesion, aerodynamic lift, materials and fibres with high mechanical strength, biological self-assembly, anti-reflection, structural coloration, thermal insulation, self-healing and sensory aid mechanisms are some of the examples found in nature, which are of commercial interest.
The word biomimetics is relatively new; however, our ancestors looked to nature for inspiration and development of various materials and devices many centuries ago. For example, the Chinese tried to make artificial silk some 3000 years ago. Leonardo da Vinci, a genius of his time, studied how birds fly and proposed designs of flying machines. In the twentieth century, various products, including the design of aircraft, has been inspired by nature. Since the 1980s, the artificial intelligence and neural networks in information technology have been inspired by the desire to mimic the human brain. The existence of biocells and DNA serves as a source of inspiration for nanotechnologists who hope to one day build self-assembled molecular-scale devices. In molecular biomimetics, proteins are being used to control materials formation in practical engineering towards self-assembled, hybrid, functional materials structure. Since the mid-1990s, the so-called lotus effect has been used to develop a variety of surfaces for superhydrophobicity, self-cleaning, drag reduction in fluid flow and low adhesion. Replication of the dynamic climbing and peeling ability of geckos has been carried out to develop treads of wall-climbing robots. Replication of shark skin has been used to develop moving objects with low drag, e.g. whole-body swimsuits. Nanoscale architecture used in nature for optical reflection and anti-reflection has been used to develop reflecting and anti-reflecting surfaces. In the field of biomimetic materials, there is an area of bioinspired ceramics based on sea shells and other biomimetic materials. Inspired by the furs of the polar bear, artificial furs and textiles have been developed. Self-healing of biological systems found in nature is of interest for self-repair. Biomimetics is also guiding in the development of sensory aid devices.
Various features found in nature's objects are on the nanoscale. The major emphasis on nanoscience and nanotechnology since the early 1990s has provided a significant impetus in mimicking nature using nanofabrication techniques for commercial applications. Biomimetics has spurred interest across many disciplines.
There are many research groups that are trying to understand the underlying mechanisms responsible for the performance of natural materials, objects and processes. Various biomimetics-inspired materials and objects are being fabricated in laboratories around the world, and some have found industrial applications. The number of publications continues to grow exponentially.
It is estimated that the 100 largest biomimetic products had generated approximately US $1.5 billion over the years 2005–2008. The annual sales are expected to continue to increase dramatically.
The two-part issues—Functional biosurfaces and Fabrication and applications—present an overview of the field of biomimetics. These should serve as a reference for a novice in the field. The issues are also intended for use by researchers who are active, or intend to become active, in the field, as well as for entrepreneurs. The appeal of these theme issues is expected to be broad. The papers generally have an overview along with new research data. Efforts are made to have sections on the future outlook in most papers to identify where the field is going. The editor has written an overview, which connects various papers into a common theme.
- © 2009 The Royal Society