Electroantennography-based Bio-hybrid Odor-detecting Drone using Silkmoth Antennae for Odor Source Localization
August 27th, 2021
This study introduces experimental protocols for a bio-hybrid odor-detecting drone based on silkmoth antennae. The operation of an experimental electroantennogram device with silkmoth antennae is presented, in addition to the structure of a bio-hybrid drone designed for odor source localization using the spiral-surge algorithm.
The bio hybrid drone with the silkmoth antennae can work with an efficient odor molecule detection tool, and a suitable flight platform for developing odor source localization algorithms. The main advantage is that the bio hybrid drone has a sensor directivity towards odor sources, because of equipping the sensor enclosure. Begin by isolating silk moth antennae using post-mortem scissors without anesthesia.
Cut both sides of the isolated silk moth antennae and use the electrically conductive gel to attach them to the silver and silver chloride coated electrodes of the sensing part of the electroantennography or EAG device. Connect the glass tube containing bombykol to the odor stimulation system, ensuring that the pump is already switched on. Build the glass tube such that its tip is 10 millimeters away from the silk mouth antennae on the EAG device.
Set the 60 millimeter diameter exhaust board 30 millimeters behind the EAG device to stabilize the airflow and prevent pheromone stagnation. Switch on the EAG device, then run the data acquisition program on the PC.Press the ground button in the log menu to decide the experimental state and then press the log start button for data acquisition. Five seconds after pressing the log start button initiate odor stimulations.
Press the log stop button on the graphical user interface, or GUI, to stop recording. Isolate silk moth antennae using post-mortem scissors and cut both sides of the antennae. Attach the isolated antennae to the silver and silver chloride coated electrodes of the sensing part of the EAG device using electrically conductive gel.
Connect the glass tube containing bombykol to the odor stimulation system with the pump already switched on. Set the glass tube so that the tube and its tip are parallel to the edge of the desk and directly above it, respectively. Set the circulator such that the center of the fan is 15 centimeters from the edge of the desk.
Set the wind speed of the circulator to one or minimum power by pushing the button on the console. Mount the EAG device on the drone. Connect the PC to the Wi-Fi access point.
Switch on the EAG device and the drone. Run the drone control program on the PC.After the light on the drone blinks yellow, press the SDK command button in the command menu on the GUI of the PC to execute the command and then press the takeoff button on the GUI to hover the drone above the ground. After pressing the flight button the log menu, to decide the experimental state, press the log start button for that acquisition.
Press the log stop button on the GUI to stop recording. Insert the sensing part of EAG device into the sensor enclosure. Set the distance between the tip of the electrodes and the tip of the enclosure as 10 millimeters.
Attached to the isolated antennae of the silk moth to the electrodes as described earlier and mount the EAG device with the sensor closure on the drone. Hover the drone so that it begins an approximately 90 degrees pivoting motion to the left and right. Stimulate the EAG device on the drone using poly droppers containing bombykol during these movements.
Conduct this step a total of four times. It was observed that the proposed EAG device reproducibly responded to the odor stimulations. The drone equipped with the EAG device hovered at the height of 95 centimeters from the floor and at a distance of 90 centimeters from the odor source.
The typical signals of the EAG device and gas sensor on the drone were recorded. For the drone without a sensor enclosure, the signal intensity at 180 degrees, when the drone faced the opposite direction from the odor source, was occasionally higher than that at zero degrees. However, for the drone equipped with the enclosure, the signal intensity of the EAG at zero degrees became higher than that at 180 degrees.
Results indicated that the drone detected bombykol in the air outside a wind tunnel and identified the direction of the odor plume by pivoting movements. Odor source localization was conducted based on this spiral search algorithm using the bio hybrid drone. The trajectory of the drone, the yaw angles and EAG signals during the odor source localization were recorded for analysis.
The EAG signals showed that the detection time, including response and recovery times, of the EAG device on the drone was approximately one second. The development with the bio hybrid drone have paved the way to construct an efficient odor molecule detection platform in the field bio hybrid robotics.
Overview
This article presents protocols for constructing and operating a bio-hybrid drone equipped with a silkmoth antenna-based electroantennography (EAG) device for real-time detection and localization of airborne odorant molecules. The system leverages the high sensitivity and selectivity of insect olfactory biosensors, offering improved performance over conventional metal-oxide-semiconductor (MOX) gas sensors for environmental monitoring and odor source localization tasks.
Key Study Components
Area of Science
- Bio-hybrid robotics
- Olfactory biosensing
- Environmental monitoring
- Drone-based sensing
Background
- Small drones with chemical or biosensor devices are valuable for environmental and security monitoring, as well as search-and-rescue operations.
- Commercial MOX gas sensors on drones have limited real-time odor detection capabilities.
- Biosensors using insect antennae provide higher sensitivity, selectivity, and faster response to odorants.
- Excised insect antennae can function as portable, high-performance odorant biosensors.
Purpose of Study
- To develop and demonstrate a bio-hybrid drone system using silkmoth antennae for real-time odorant detection.
- To enhance sensor directivity and odor source localization using a sensor enclosure and spiral-surge search algorithm.
- To provide experimental protocols for assembling and operating the system.
Methods Used
- Isolation and preparation of silkmoth antennae for use as biosensor elements.
- Attachment of antennae to silver/silver chloride electrodes on the EAG device using conductive gel.
- Odor stimulation using bombykol delivered via a glass tube and controlled airflow setup.
- Mounting the EAG device (with and without sensor enclosure) on a small autonomous drone.
- Real-time data acquisition and drone control via Wi-Fi and PC interface.
- Odor source localization using a spiral-surge search algorithm and drone pivoting maneuvers.
Main Results
- The EAG device with silkmoth antennae reproducibly detected odorant (bombykol) stimuli in real time.
- The sensor enclosure improved directivity, enabling the drone to better identify the direction of the odor source.
- The drone successfully localized odor sources in a pseudo-open environment outside a wind tunnel.
- The EAG device demonstrated rapid response and recovery times (approximately one second) during odor detection.
Conclusions
- The bio-hybrid drone system provides efficient, real-time odor molecule detection and localization capabilities.
- Sensor enclosure design enhances directional sensing performance.
- This platform is suitable for further development of odor source localization algorithms and field applications in bio-hybrid robotics.
Frequently Asked Questions
Executive Industry Relevance
Integrating silkmoth antennae-based electroantennography (EAG) biosensors onto autonomous drones addresses the challenge of real-time, high-sensitivity odorant detection in complex environments. This bio-hybrid platform enhances predictive confidence for odor source localization, supporting early-stage validation of environmental and security monitoring technologies. The approach enables robust, reproducible detection workflows that can be adapted for scalable R&D pipelines in biosensing and robotics.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables interrogation of biological olfactory pathways using insect antennae as functional biosensors.
- Supports mechanistic de-risking by providing high-sensitivity, selective detection of volatile molecules.
- Facilitates predictive confidence in biosensor performance for environmental and security applications.
Screening & Assay Development
- Prepares validated bio-hybrid systems for downstream odorant screening workflows.
- Delivers reproducible, quantitative EAG signal outputs for assay standardization.
- Enables scalable evaluation of sensor enclosure designs and localization algorithms.
Translational & Preclinical Research
- Aligns biosensor outputs with real-world environmental detection scenarios.
- Supports continuity from discovery-stage biosensor validation to preclinical field testing.
- Provides a platform for risk-adjusted advancement of bio-hybrid detection technologies.
Pipeline & Workflow Integration
This EAG-based odor detection method fits within the discovery-to-preclinical continuum for biosensor development and environmental monitoring solutions.
- Discovery Biology: Enables hypothesis testing of insect olfactory system sensitivity and selectivity in engineered platforms.
- Screening: Provides reproducible, quantitative EAG measurements for comparing sensor configurations and algorithms.
- Analytics: Generates real-time signal outputs and trajectory data for cross-condition analysis.
- Translational Research: Bridges laboratory biosensor validation with field-relevant odor localization tasks.
- Enterprise Reuse: Establishes a modular, programmable platform for iterative biosensor and algorithm development.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence and reduces mechanistic ambiguity in odorant detection workflows.
- Operational Value: Standardizes biosensor preparation, data acquisition, and drone integration for reproducibility.
- Strategic Value: Improves go/no-go decisions for advancing biosensor platforms and localization algorithms.
- Portfolio Impact: Supports risk-adjusted prioritization of bio-hybrid detection technologies for environmental and security applications.
Implementation Considerations
- Requires expertise in insect olfactory biology and EAG signal analysis.
- Needs instrumentation for precise antennae preparation, electrode attachment, and airflow control.
- Demands cross-team standardization of biosensor mounting and data acquisition protocols.
- Must adapt sensor enclosure and drone integration for different environmental conditions.
- Performance may vary with antennae viability and environmental airflow dynamics.
Biopharma FAQs
Chapters in this video
0:05
Introduction
0:27
EAG Experiments on a Fixed Desk Surface
1:49
EAG Experiments on the Drone and Sensor Enclosure
3:33
Odor Tracing Demonstration Using the Bio-hybrid Drone
4:08
Results: Bio-hybrid Odor-detecting Drone Using Silkmoth Antennae for Odor Source Localization
5:34
Conclusion
