Detection of a surrogate biological agent with a portable surface plasmon resonance sensor onboard an unmanned aircraft system

Abstract

A system was developed to perform near real-time biological threat agent (BTA) detection with a small autonomous unmanned aircraft system (UAS). Biological sensors recently reached a level of miniaturization and sensitivity that have made UAS integration a feasible task. A surface plasmon resonance (SPR) biosensor was integrated into a small UAS platform for the first time, providing the UAS with the capability to collect and then quantify the concentration of a surrogate biological agent in near realtime. The sensor operator ran the SPR unit through a ground-station laptop, viewing the sensor data in real time during flight. An aerial sampling mechanism was also developed for use with the SPR sensor. The sampling system utilized a custom impinger setup to collect and concentrate aerosolized particles. The SPR and sampling system's feasibility was demonstrated using an aerosolized sucrose solution as a mock BTA. Three field experiments were carried out to test and validate the biological sampling system. In the first field experiment, the collection system was tested by flying the UAS through a ground-based plume of water-soluble blue dye. In the second field experiment, a sucrose solution was autonomously aerosolized, collected, and then detected by the combined sampling and SPR sensor subsystems onboard the UAS. In the third field experiment, a dye was released from one UAS (the leader) and captured by another UAS (the follower). Together, these field experiments illustrate the capability of the UAS to detect and quantify the concentration of a BTA released at altitude. Our integrated SPR system sets the stage for future work to detect and track BTAs in the atmosphere and assist in localizing their sources.