Self-powered aquatic robot for ocean sensing
Researchers in the US have developed an aquatic ‘bug’ powered by bacteria that can be used for ocean monitoring.
The US Defense Advanced Research Projects Agency (DARPA) has started a program called the Ocean of Things and the team at Binghamton University in New York used their previous research on microbial fuel cell (MFC) to power the aquatic robot.
The research showed power generation close to 1 milliwatt, which is enough to operate the robot’s mechanical movement and any sensors that could track environmental data such as water temperature, pollution levels, the movements of commercial vessels and aircraft, and the behaviours of aquatic animals.
To ensure a steady supply of organic substrates for microbial viability, a biomimetic Janus membrane with asymmetric surface wettability is integrated, enabling selective substrate intake. The Janus interface is hydrophilic on one side and hydrophobic on the other, lets in nutrients from the water and keeps them inside the device to fuel bacterial spore production.
Additionally, stability mechanisms inspired by water striders allow the robot to move efficiently across water surfaces. The robot mimics the water strider’s movement using a motor powered by microbial metabolism.
“When the environment is favourable for the bacteria, they become vegetative cells and generate power,” said Professor Seokheun “Sean” Choi, director of the Center for Research in Advanced Sensing Technologies and Environmental Sustainability (CREATES). “But when the conditions are not favourable — for example, it’s really cold or the nutrients are not available — they go back to spores. In that way, we can extend the operational life.”
“We used very common bacterial cells, but we need to study further to know what is actually living in those areas of the ocean,” said Choi “Previously, we demonstrated that the combination of multiple bacterial cells can improve sustainability and power, so that’s another idea. Maybe using machine learning, we can find the optimal combination of bacterial species to improve power density and sustainability.”
Being able to send the robots wherever they are needed is a clear upgrade from current “smart floats,” which are stationary sensors anchored to one place.
The next step in refining these aquatic robots is testing which bacteria will be best for producing energy under stressful ocean conditions.
10.1002/admt.202400426; www.binghampton.edu
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