A team of scientists from RIKEN, Waseda Univerisity, the Fukui University of Technology and the Nanyang Technological University has created a cyborg cockroach that uses a mounted ultrasoft organic solar cell module that does not impair the insect’s basic motion abilities.
Kakei et al. established a design strategy for mounting electronics on insects through systematic evaluation of motion abilities and demonstrated charging and wireless locomotion control on living cyborg insects. Image credit: Kakei et al., doi: 10.1038/s41528-022-00207-2.
“Cyborgs, which are integrations of machines and organisms, can be used not only to substitute an organism’s defective body parts, but also to realize functions that exceed the organism’s normal capabilities,” said RIKEN researcher Kenjiro Fukuda and colleagues.
“Advancements in electronics have resulted in the increasing integration of organisms and machines.”
“The miniaturization and fabrication of low-power consumption semiconducting chips through micro/nanofabrication have resulted in small-organism cyborgs.”
“In particular, cyborg insects with small integrated circuits to control their behavior have been proposed for applications such as urban search and rescue, environmental monitoring, and inspection of dangerous areas.”
“Body-mounted energy-harvesting devices are critical for expanding the range of activity and functionality of cyborg insects,” they said.
“However, their power outputs are limited to less than 1 mW, which is considerably lower than those required for wireless locomotion control.”
“The best solution is to include an on-board solar cell that can continuously ensure that the battery stays charged.”
In their research, the authors experimented with Madagascar hissing cockroaches (Gromphadorhina portentosa).
They attached the wireless leg-control module and lithium polymer battery to the top of the insect on the thorax using a specially designed backpack.
The backpack was 3D printed with an elastic polymer and conformed perfectly to the curved surface of the cockroach, allowing the rigid electronic device to be stably mounted on the thorax for more than a month.
The ultrathin (0.004-mm thick) organic solar cell module was mounted on the dorsal side of the insect’s abdomen.
“The body-mounted ultrathin organic solar cell module achieves a power output of 17.2 mW, which is more than 50 times larger than the power output of current state-of-the art energy harvesting devices on living insects,” Dr. Fukuda said.
The ultrathin and flexible organic solar cell, and how it was attached to the insect, proved necessary to ensure freedom of movement.
After carefully examining natural cockroach movements, the researchers realized that the abdomen changes shape and portions of the exoskeleton overlap.
To accommodate this, they interleaved adhesive and non-adhesive sections onto the films, which allowed them to bend but also stay attached.
When thicker solar cell films were tested, or when the films were uniformly attached, the cockroaches took twice as long to run the same distance, and had difficulty righting themselves when on their backs.
Once these components were integrated into the cockroaches, along with wires that stimulate the leg segments, the cyborg insects were tested.
The battery was charged with pseudo-sunlight for 30 minutes, and animals were made to turn left and right using the wireless remote control.
“Considering the deformation of the thorax and abdomen during basic locomotion, a hybrid electronic system of rigid and flexible elements in the thorax and ultrasoft devices in the abdomen appears to be an effective design for cyborg cockroaches,” Dr. Fukuda said.
“Moreover, since abdominal deformation is not unique to cockroaches, our strategy can be adapted to other insects like beetles, or perhaps even flying insects like cicadas in the future.”
The work was published in the journal npj Flexible Electronics.
_____
Y. Kakei et al. 2022. Integration of body-mounted ultrasoft organic solar cell on cyborg insects with intact mobility. npj Flex Electron 6, 78; doi: 10.1038/s41528-022-00207-2
