Flexible solar panels do not interfere with the movements of the "robotic" insect and allow it to recharge its onboard electronics in half an hour.
Microscopic robots that can squeeze into any crevice will be useful for a variety of tasks, from finding people under rubble to studying the environment. And while some developers are working on miniature machines, others are turning them into living insects. A few years ago, for example, scientists managed to control the roach's movements using electrodes connected to its nervous system.
Now the system has been significantly upgraded: a wireless communication module, a rechargeable battery and a solar cell to power the on-board electronics have been added to the cyborg cockroach's arsenal. Researchers from the Japanese Institute of Physical and Chemical Research (RIKEN) wrote about it in an article published in the journal npj Flexible Electronics.
Kenjiro Fukuda and his colleagues worked with a rather large Madagascar hissing cockroach, which reaches about six centimetres in length. To accommodate the necessary components, the scientists designed a 'backpack' shaped to fit comfortably on the insect's back. This structure was 3D-printed from an elastic polymer and fixed in place with glue, where it was safely kept for more than a month. A microchip, communication system and other hard and relatively massive components were placed in this 'backpack'.
Below, on the dorsal side of the cockroach's abdomen, scientists installed organic solar panels just 0.004 millimetre thick. Their power output reaches 17.2 milliwatts, dozens of times the capacity of other energy sources that have so far succeeded in producing insect cyborgs. Ultra-thin and flexible, these batteries are attached only to individual segments of the cockroach exoskeleton. This allows them to shift relative to each other when the abdomen bends and does not hinder movement.
As in the previous version, the system uses electrodes attached to the insect's motor neurons. Experiments in the lab have shown that it takes half an hour under simulated sunlight to fully charge, after which the cyborg obediently follows commands received wirelessly for two hours.