Turning nature into a factory
How a salamander inspired a robot, a protein became a sensor and a molecule helped design a water purifier.
- The number of biomimicry patents, research articles and grants has increased more than fivefold since 2000.
- A Danish biotech start-up has developed a technology which, taking its cue directly from nature, can separate water from all other compounds.
Take, for example, the obvious biomimicry of the École Polytechnique Fédérale de Lausanne salamander robot (named Pleurobot). Capable of walking and swimming, Pleurobot can replicate the amphibian’s movement to an unprecedented degree of accuracy.
“The robot has been designed as a scientific tool for neuroscience,” project leader Auke Ijspeert explained during a TedTalk, and yet applications are already being touted – like search and rescue, fieldwork and archaeology, and for industrial inspection, painting and coating.
This robot, capable of walking and swimming, could be used for search and rescue missions, as well as for industrial inspection.
Some natural designs, like the salamander’s amphibious capabilities, the hedgehog’s armour or the humming bird’s nectar-sipping beak, confer clear evolutionary advantages. Others are a little more mystifying – but could offer huge benefits to industry.
Just this kind of mystery is what Professor Ulrich Gerland and his team of physicists from the Technical University of Munich aimed to illuminate when they joined a project by a group of biologists from Ludwig Maximilian University of Munich (LMU). The project’s aim was to understand the role of a certain protein in Escherichia coli – a bacterium commonly found in the intestines of warm-blooded animals, including humans. “The LMU group already had some evidence that the membrane protein KdpD could be a dual sensor for potassium,” explains Gerland. “The question was why the dual sensor was useful when a single sensor should be able to do the job.”
Testing various designs, it slowly became clear that the dual sensor is better when both the availability and demand for potassium by the bacterium fluctuate. “This suddenly made a lot of sense – the external sensor is a useful design when the external concentration (supply) of potassium mainly fluctuates, whereas the internal sensor is advantageous primarily when the demand for potassium fluctuates.” The beauty of the dual sensor is that it can deal with both types of fluctuations simultaneously.
The KdpD dual sensor has been likened to sophisticated temperature control in modern heating systems and other control schemes, but it does so without computer memory or processing power or wires or electricity, and all at the nanoscale. “It is absolutely amazing how KdpD combines dual sensors and dual controllers into a single nanometresized molecule,” says Gerland. “Where engineering can primarily learn from biology is on the level of system integration and miniaturisation.”
Water of life
Another industrial area in which biomimicry is making waves is water purification. Water is essential to the industrial sector – from heating, cooling, processing, cleaning and rinsing processes to essential components of manufactured products like beverages and pharmaceuticals. But if not treated correctly, it can also be a source of problems: corroding and fouling essential materials, reducing the quality of manufactured products, and even posing health risks. So, any technology capable of purifying water cheaply and effectively will pique the interest of industrial leaders.
This is the exact reason Aquaporin A/S, a Danish biotech start-up, is attracting interest from the sector. “The Aquaporin Inside Membrane technology can be seen as a generic technology capable of separating water from all other compounds,” explains Aquaporin Vice President and Technical University of Denmark Associate Professor Claus Hélix-Nielsen. “We are currently focusing on making membranes for household purifiers and also treatment of industrial wastewater.”
So far, so unremarkable, but under the hood the Aquaporin technology takes its cue directly from nature. “Aquaporin molecules are a special class of proteins normally residing in cell membranes where they essentially act as very efficient selective water channels,” Hélix-Nielsen explains. “We use these proteins as building blocks in the fabrication of the membranes.”
The Aquaporin team has looked far beyond industrial applications, investigating its use to make clean drinking water for the almost 800 million people globally who do not have access to potable water, and even working with NASA and the European Space Agency to improve water purification on board the International Space Station. Their membrane filter uses Aquaporin proteins to pull clean water out of urine, sweat, wastewater, condensation and other liquid sources available in space.
After recently being tested by the first Danish astronaut, the Aquaporin solution proved lighter, quicker, more robust, more energy-efficient and cheaper than the existing filtration device on the space station. A future version of the technology may even find itself aboard trips to Mars later in the century.
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