In Brief
- A new hybrid sensor combines living organisms with synthetic sensors to improve chemical sensing abilities.
- McKelvey Engineering’s Srikanth Singamaneni and Barani Raman combined talents to augment insects with sample collection materials.
- Such locusts could someday help with search-and-rescue, detect chemical weapons and map disaster zones.
Scientists have long explored the idea of using insects as our agents in the field in places where humans won’t fit or survive. Imagine a cockroach in an earthquake zone, able to skitter into the rubble to map out exactly where human chemical signatures can be found; or a grasshopper leaping through a minefield to bring back a map of the bombs based on the vapors it encountered. Recent research from Washington University in St. Louis brings this sci-fi concept one step closer to reality.
“We marry the best biology has to offer with engineering principles to create a superior sensing system,” said Barani Raman, the Dennis & Barbara Kessler Professor in biomedical engineering at the WashU McKelvey School of Engineering.
Raman and his colleague Srikanth Singamaneni, the Lilyan & E. Lisle Hughes Professor in mechanical engineering and materials science, are senior authors of research now published in the journal Advanced Materials. The study describes a hybrid chemical sensing system combining an insect’s natural sensing abilities with nanomaterials to help collect and identify chemical samples.
Both biological and artificial chemical sensing systems have drawbacks, Singamaneni said. A locust’s olfactory system is extremely sensitive and can detect faint odors that guide its behavior. But even with 50,000 olfactory receptor neurons in each antenna, it can’t identify a wide enough range of chemical compounds. Meanwhile, synthetic sensors don’t perform as well as more nimble living creatures, but they can be very accurate at detecting specific compounds. Why not combine the two?
“Both biological and artificial chemical sensing approaches have their strengths and drawbacks,” said Singamaneni, but by combining them, “you can cast a broader net.” Here, they added an ultralight, highly porous nanomaterial coating, known as surface-enhanced Raman scattering (SERS) substrate, to the locusts’ antennae.
SERS is a technique that boosts signals from molecules on or near nanostructure metal surfaces; it’s especially useful for detecting trace chemicals. In this case, researchers used a collagen foam applied to the antennae or wings. The foam augmented the insect’s odor-detecting skills without interfering with its other functions.
Singamaneni’s lab specializes in designing and synthesizing these types of nanomaterials. He has been working with plasmonic nanostructures as long as Raman has been mapping locust sensory circuits. They melded their research, and it paid off. Locusts equipped with the foam outperformed non-SERS locusts as well as synthetic chemical sensors, improving odor-detection performance across all chemicals tested, including the chemical signature for TNT.
In a series of tests, their hybrid systems successfully detected a wider range of smells without affecting the insect’s normal functions.
Raman said a key challenge in chemical sensing is they often don’t know what molecules they’re targeting. The foam attached to the antenna helps identify particular chemical species, he noted. The biology and the chemical sensing parts complement each other.
“It clearly showed the best of the two worlds can be merged,” he said.
A. Debnath, P. Gupta, R. Gupta, et al. “ Plasmonic Foam-Enabled Dual-Modal Biohybrid Chemical Sensor.” Advanced Materials (2026): e75082. https://doi.org/10.1002/adma.75082
Research supported by the Air Force Office of Scientific Research (FA95502310461) and the National Science Foundation (CSE-2319060, CBET-2331330).
