Explosive sensing with insect-based biorobots

Abstract

Stand-off chemical sensing is an important capability with applications in several domains including homeland security. Engineered devices for this task, popularly referred to as electronic noses, have limited capacity compared to the broad-spectrum abilities of the biological olfactory system. Therefore, we propose a hybrid bio-electronic solution that directly takes advantage of the rich repertoire of olfactory sensors and sophisticated neural computational framework available in an insect olfactory system. We show that select subsets of neurons in the locust (Schistocerca americana) brain were activated upon exposure to various explosive chemical species (such as DNT and TNT). Responses from an ensemble of neurons provided a unique, multivariate fingerprint that allowed discrimination of explosive vapors from non-explosive chemical species and from each other. Notably, target chemical recognition could be achieved within a few hundred milliseconds of exposure. Finally, we developed a minimally-invasive surgical approach and mobile multi-unit electrophysiological recording system to tap into the neural signals in a locust brain and realize a biorobotic explosive sensing system. In sum, our study provides the first demonstration of how biological olfactory systems (sensors and computations) can be hijacked to develop a cyborg chemical sensing approach. SUMMARY: We demonstrate a bio-robotic chemical sensing approach where signals from an insect brain are directly utilized to detect and distinguish various explosive chemical vapors.

Across-animal odor decoding by probabilistic manifold alignment

“…The alignment of low-dimensional neural manifolds is equally important in brain-computer interface (BCI) applications, where the assumption of a common low dimensional structure in neural responses is used to compensate for instability in neural recordings and ensure robust performance over time [8,9]. This is not only restricted to motor control; in the sensory domain, a new generation of chemical detectors exploit the unsurpassed sensitivity of rodent olfactory receptors, but bypass the limitations of training animals to report odor identity by directly decoding it from neural responses [10,11,12]. Unfortunately, the applicability of this idea is limited by the need to learn the mapping between neural activity and chemical identity on an animal-by-animal basis, which involves costly data collection [13].…”

Harnessing insect olfactory neural circuits for noninvasive detection of human cancer

“…We observed VOC-evoked changes in neural spiking responses in most of the PNs recorded. Since PNs are broadly selective to several odor stimuli and respond to specific odorants or odor mixtures with distinctive temporal firing patterns 22–24,51 , we targeted this neuron population for oral cancer classification. At the individual neuron level, the three oral cancer and the non-cancer VOC mixtures elicited distinct spiking responses over the odor presentation window.…”

“…These lost signals from unresolved neurons could potentially be important for odor discrimination, therefore, we decided to employ the R.M.S.-based approach which takes into account the total energy of the signal acquired from each location. This approach was computationally less expensive, unsupervised and shown to be odor specific in our earlier work 22 . Using the R.M.S.…”

“…Insect olfactory sensory systems are extremely powerful and have evolved to detect low concentrations of gas molecules and minute changes in the composition of gas mixtures 22–25 . Moreover, the locust olfactory system is well studied for odor-evoked neural coding schemes 26–47 , and is accessible for electrophysiological recordings from multiple olfactory brain centers 27,38,47,48 .…”

Ear-Bot: Locust Ear-on-a-Chip Bio-Hybrid Platform

“…Since the presentation of the first bio-hybrid robot, which used the silkworm moth’s antenna to measure pheromone concentration in the air [ 2 ], other bio-hybrid robots were developed, utilizing various biological sensors in order to provide input to robotic platforms. These include the use of olfactory systems to identify the source of odorants [ 3 , 4 , 5 , 6 ], and even to distinguish between odorant concentrations emitted by explosives [ 7 ]; photoreceptors, which are used for optical guidance [ 8 , 9 ]; and even a bio-inspired light-guided swimming robot that mimics a ray fish and was powered by rat heart muscle cells [ 10 ]. To the best of our knowledge, none of these examples to date, used an insect auditory system.…”