Robotic coral removes contaminants from water

Robotic coral polyps have sucked in and trapped simulated contaminants in water, leading the way towards artificial systems that could clean dirty aquatic environments.

Researchers at the University of Warwick’s WMG, led by Eindhoven University of Technology in the Netherlands, developed the 1x1cm wireless device. 

Naturally occurring corals are formed of polyps, small creatures with stems and tentacles that generate currents and provide nourishment.  

To replicate the biological system, the researchers used a magnetic field and light to wirelessly control the artificial polyp. The rotating magnetic field rotates the polyp’s stem, causing an attractive flow to guide suspended targets – such as oil droplets – towards the device.  

Once targets are within reach, UV light activates the polyp’s tentacles – composed of photo-active liquid crystal polymers – which bend towards the light and enclose the droplet. The target can then be released by shining blue light on the tentacles.  

Devices based on the artificial polyps could clean water or even be used in medical diagnostic devices, picking up and transporting specific cells for analysis.   

Dr Harkamaljot Kandail from the WMG created 3D simulations of the aquatic devices. The simulations helped understand how the flow of water could attract particles, and optimised the shape of the tentacles.  

"Corals are such a valuable ecosystem in our oceans, I hope that the artificial aquatic polyps can be further developed to collect contaminant particles in real applications,” said Dr Kandail. “The next stage for us to overcome before being able to do this is to successfully scale up the technology from laboratory to pilot scale. To do so we need to design an array of polyps which work harmoniously together, where one polyp can capture the particle and pass it along for removal." 

Marina Pilz Da Cunha from Eindhoven University of Technology said: "The artificial aquatic polyp serves as a proof of concept to demonstrate the potential of actuator assemblies and serves as an inspiration for future devices. It exemplifies how motion of different stimuli-responsive polymers can be harnessed to perform wirelessly-controlled tasks in an aquatic environment." 

The research was published in Proceedings of the National Academy of Sciences.  

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