Biomimicry or biomimetics is the examination of nature, its models, systems, processes, and elements to emulate or take inspiration from in order to solve human problems. The term biomimicry and biomimetics come from the Greek words bios, meaning life, and mimesis, meaning to imitate. Other terms often used are bionics, bio-inspiration, and biognosis.
Through the course of 4.8 billion years, nature has gone through a process of trial and error to refine the living organisms, processes, and materials on planet Earth. The emerging field of biomimetics has given rises to new technologies created from biologically inspired engineering in both the macro scale and nanoscale levels. Biomimetics is not a new idea. Humans have been looking at nature for answers to both complex and simples problems since our existence. Nature has solved many of todays engineering problems such as hydrophobicity, wind resistance, self-assembly, and harnessing solar energy through the evolutionary mechanics of selective advantages.
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One of the early examples of biomimicry was the study of birds to enable human flight. Although never successful in creating a "flying machine", Leonardo da Vinci (1452–1519) was a keen observer of the anatomy and flight of birds, and made numerous notes and sketches on his observations as well as sketches of various "flying machines".[1] The Wright Brothers, who finally did succeed in creating and flying the first airplane in 1903, also derived inspiration for their airplane from observations of pigeons in flight.[2]
Otto Schmitt, an American academic and inventor, coined the term biomimetics to describe the transfer of ideas from biology to technology. The term biomimetics only entered the Websters 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".
In 1960, the term bionics was coined by psychiatrist and engineer Jack Steele to mean "the science of systems which have some function copied from nature".[3] Bionics entered the Webster dictionary in 1960 as "a science concerned with the application of data about the functioning of biological systems to the solution of engineering problems". The term bionic took on a different connotation when Martin Caidin referenced Jack Steele and his work in the novel "Cyborg" which later resulted in the 1974 television series "The Six Million Dollar Man" and its spin-offs. The term bionic then became associated with 'the use of electronically operated artificial body parts' and 'having ordinary human powers increased by or as if by the aid of such devices'.[4] Because the term bionic took on the implication of super natural strength, the scientific community in English speaking countries shied away from using it in subsequent years.[5]
The term biomimicry appeared as early as 1982.[6] The term biomimicry was popularized by scientist and author Janine Benyus in her 1997 book Biomimicry: Innovation Inspired by Nature. Biomimicry is defined in her book as a "new science that studies nature's models and then imitates or takes inspiration from these designs and processes to solve human problems". Benyus suggests looking to Nature as a "Model, Measure, and Mentor" and emphasizes sustainability as an objective of biomimicry.[7]
The San Diego Zoo started its biomimicry programs in 2007, and recently commissioned an Economic Impact Study to determine the economic potential of biomimicry. The report was titled Biomimicry: An Economic Game Changer and estimated that biomimicry would have a $300 billion annual impact on the US economy, plus add an additional $50 billion in environmental remediation.
Biological imitation of nano and macro scale structures and processes is called nanobiomimicry. Nature provides a great variety of nano-sized materials that offer as potential templates for the creation of new materials eg. bacteria, viruses, diatoms, and biomolecules. Through the study of nanobiomimicry, key components of nanodevices like nanowires, quantum dots, and nanotubes have been produced in an efficient and simple manner when compared to more conventional lithographic techniques. Many of these biologically derived structures are then developed into applications for photovoltaics, sensors, filtration, insulation, and medical uses. The field of nanobiomimetics is highly multidisciplinary, and requires collaboration between biologists, engineers, physicists, material scientists, nanotechnologists and other related fields. In the past century, the growing field of nanotechnology has produced several novel materials and enabled scientists to produce nanoscale biological replicas.
Biomorphic mineralization is a technique that produces materials with morphologies and structures resembling those of natural living organisms by using bio-structures as templates for mineralization. Compared to other methods of material production, biomorphic mineralization is facile, environmentally benign and economic [8] Biomorphic mineralization makes efficient use of natural and abundant materials such as calcium, iron, carbon, phosphorous, and silicon with the capability of turning biomass wastes into useful materials. Templates derived from biological nanoparticles such as DNA, viruses, bacteria, and peptides can transform unordered inorganic nanoparticles into complex inorganic nanostructures. Biologically derived nanostructures are typically fabricated using either chemical or physical techniques. Typical chemical fabrication techniques are plasma spraying, plasma immersion ion implantation & deposition (PIII&D), sol–gel, chemical vapor deposition (CVD), physical vapor deposition (PVD), cold spraying, self-assembly, and so on, whereas in physical modification techniques include laser etching, shot blasting, physical plating, and physical evaporation and deposition etc. Methods of fabrication with high throughput, minimal environmental damage, and low costs are highly sought after.
The use of biomineralized structures is vast and derived from the abundance of nature. From studying the nano-scale morphology of living organisms many applications have been developed through multidisciplinary collaboration between biologists, chemists, bioengineers, nanotechnologists, and material scientists.
A virus is a nonliving subatomic particle ranging from the size of 20 to 300 nm capsules containing genetic material used to infect its host. The outer layer of viruses have been designed to be remarkably robust and capable of withstanding temperatures as high as 60 ̊C and stay stable in a wide range of pH range of 2-10 [8] (Tong-Xiang). Viral capsids can use to create several nano device components such as nanowires, nanotubes, and quantum dots. Tubular virus particles such as the tobacco mosaic virus (TMV)can be used as templates to create nanofibers and nanotubes since both the inner and outer layers of the virus are charged surfaces and can induce nucleation of crystal growth. This was demonstrated by Dujardin et al. though the production of Pt and Au nanotubes using TMV as a template [9]. Shenton Douglas, a researcher from Montana State University, demonstrated the mineralized virus particles could withstand various pH values by mineralizing the viruses with different materials such silicon, PbS, and CdS and could therefore serve as a useful carriers of material [10]. A spherical plant virus called cowpea chloric mottle virus (CCMV) has interesting expanding properties when exposed to environments of pH higher than 6.5. Above this ph, 60 independent pores with diameters about 2nm begin to exchange substance with the environment. The structural transition of the viral capsid can be utilized in Biomorphic mineralization for selective uptake and deposition of minerals by controlling the solution pH. Applications include using the viral cage to produce uniformly shaped and sized quantum dot semiconductor nanoparticles through a series of pH washes. This is an alternative to the apoferritin cage technique currently used to synthesize uniform CdSe nanoparticles [11]. Such materials could also be used for targeted drug delivery since particles release contents upon exposure to certain pH.
Morpho butterfly wings contain microstructures that create its coloring effect through structural color rather than pigmentation. Incident light waves are reflected at specific wavelengths to create vibrant colors due to multilayer interference, diffraction, thin film interference, and scattering properties. The scales of the butterflies consist of microstructures like ridges, cross-ribs, ridge-lamellae, and microribs that have been shown to be responsible for coloration. The structural color has been simply explained as the interference due to alternating layers of cuticle and air using a model of multilayer interference. The same principles behind the coloration of soap bubbles apply to butterfly wings. The color of butterfly wings is due to the multiple instances of constructive interference from this structure. The photonic microstructure of the butterfly wings can be replicated through biomorphic mineralization to yield similar properties. The photonic microstructures can be replicated using metal oxides or metal alkoxides such as TiSO4, ZrO2, and Al2O3. An alternative method of vapor-phase oxidation of SiH4 on the template surface was found to preserve delicate structural features of the microstructure [12] Now, companies like Qualcomm are specializing in creating color displays with low power consumption based on these principles. Other organisms with similar iridescence properties include mother of pearl seashells, fish, and peafowl.
Researchers, for example, studied the termite's ability to maintain virtually constant temperature and humidity in their termite mounds in Africa despite outside temperatures that vary from 1.5 °C to 40 °C (35 °F to 104 °F). Researchers initially scanned a termite mound and created 3-D images of the mound structure, which revealed construction that can influence human building design. The Eastgate Centre, a mid-rise office complex in Harare, Zimbabwe, (highlighted in this Biomimicry Institute case-study) stays cool without air conditioning and uses only 10% of the energy of a conventional building its size.
Modeling echolocation in bats in darkness has led to a cane for the visually impaired. Research at the University of Leeds, in the United Kingdom, led to the UltraCane, a product formerly manufactured, marketed and sold by Sound Foresight Ltd.
Janine Benyus refers in her books to spiders that create web silk as strong as the Kevlar used in bulletproof vests. Engineers could use such a material—if it had a long enough rate of decay—for parachute lines, suspension bridge cables, artificial ligaments for medicine, and many other purposes.[7]
Other research has proposed adhesive glue from mussels, solar cells made like leaves, fabric that emulates shark skin, harvesting water from fog like a beetle, and more. Nature’s 100 Best is a compilation of the top hundred different innovations of animals, plants, and other organisms that have been researched and studied by the Biomimicry Institute.
A display technology based on the reflective properties of certain morpho butterflies was commercialized by Qualcomm in 2007. The technology uses Interferometric Modulation to reflect light so only the desired color is visible to the eye in each individual pixel of the display.
Biomimicry may also provide design methodologies and techniques to optimize engineering products and systems. An example is the re-derivation of Murray's law, which in conventional form determined the optimum diameter of blood vessels, to provide simple equations for the pipe or tube diameter which gives a minimum mass engineering system.[13]
A novel engineering application of biomimetics is in the field of structural engineering. Recently, researchers from Swiss Federal Institute of Technology (EPFL) have been incorporating biomimetic characteristics in an adaptive deployable tensegrity bridge . The bridge can carry out self-diagnosis and self-repair.[14]