Visual biomimicry: Innovations inspired by nature
Biomimicry is an approach that seeks solutions to human challenges by imitating nature’s time-tested patterns and strategies. Three billion years of evolution has refined the designs seen in the natural world. These are now contributing to fields such as material science, engineering, architecture, robotics, and medicine.
One particularly impressive example can be seen in the shark-inspired boats conceived by NASA, whose scientists developed a drag-reducing coating for ships inspired by the microscopic scales on shark skin. These scales, called denticles, are akin to tiny teeth. They reduce drag by creating turbulences at the water interface, preventing the viscous ‘boundary layer’ that normally forms around objects moving in a fluid. The shark-inspired technological innovation was ultimately deemed an unfair advantage for the winning team of the America’s Cup sailing race in 1987, upon which the technology was shortly banned.
Likewise, a myriad of gecko-skin technology has borrowed the key element of the gecko’s gravity defying grip: rows of tiny hairs, known as setae, which cling to almost any conceivable surface. The attraction of each hair is minute, working through simple electrostatic attractions, but the net effect is extremely powerful. It has been estimated that the setae from the tiny toe of a gecko could carry 113kg. From this an incredible adhesive has been developed, with setae-imitation structures so strong that an index-card strip can hold up to 318kg.
The way animals perceive the world around them is providing fascinating inspiration for the field of optics and machine vision. Evolution has created remarkably refined imaging systems in various fauna, with complex, image-forming eyes evolving independently some 50 to 100 times over the last few million years. Invertebrate arthropods in particular offer enticing technological solutions, the phylum consists of animals such as cephalopods and insects.
Arthropods have compound eyes, which are made up of hundreds of tiny lenses working as a collective. The complex eye consists of long, cylindrical units called ommatidia, clustered together in a dome with the lenses facing outward. The compound eye is able to see with an almost infinite depth of field, almost all the way around the organism, and it is able to maintain both far and near objects in constant focus.
From this, scientists have created the first working compound eye style camera which mimics the arthropod eye. The camera possesses a curved lens made up of 180 individual smaller lenses. Taking nature as a guide to produce these imitation ommatidia provides the possibility of creating a curved lens, as opposed to the flat lens of cameras. This offers a field view of 160 degrees without the peripheral distance and light distortion that are commonplace in traditional wide-capture lenses. Like a compound eye, this impressive feat of engineering boasts an infinite depth of field, having both far and near objects constantly in focus. Its potential uses include security surveillance, providing exceptionally high quality medical imaging, and advancing the use of unmanned flying vehicles.
Further inspiration has come from one of the most intricate eye designs found in nature. Boasting 16 types of colour receptors, compared to humans’ 3, and with the ability to sense polarisation, the mantis shrimp’s eyes are unmatched by most. This unique sea creature has inspired researchers to create an ultra-sensitive handheld camera that too, can see both colour and polarisation.
The mantis shrimp’s six polarisation channels have been the guide for this camera’s creation. Light consists of electromagnetic vibrations in the form of a wave. When light reflects off a surface or passes through a filter, the resulting vibrations of the light wave occur in a single plane. This light wave is now said to be polarised. Humans can’t detect this change, but many animal species use polarised vision as a surreptitious form of communication, used to find food or even navigate by sensing the polarisation patterns in the sky.
The mantis shrimp eye stacks light-sensitive elements on top of one another, this period organisation of these eye stacks allows it to see the polarised properties of light. Researchers have stacked multiple photodiodes in silicon, which has been combined with metallic nanowires. This creates a polarisation detecting camera that could facilitate everything from detecting cancer, whose disorganised structures scatter light differently than normal cells, to monitoring changes in the environment.
Technology taken from nature’s model has revealed a world unbeknownst to us, exposing covert communication channels and facilitating cancer detection using animal vision.. Biomimicry involves emulating life’s genius in order to improve technology. Arthropods have had the luxury of 530 million years of evolution through natural selection. Our species, in comparison, only evolved some 200,000 years ago, meaning we have been around for a mere 0.004% of the Earth’s history. It is only fitting that we should look to these tried and tested designs that have been developed before our species had even evolved.