Fluorescent Bubble Sensor Array and a Conceptual Platform for High-Performance Sensing of Gaseous Nerve Agent Simulants

Bubble optical sensors and droplet microreactors, featuring the intrinsic advantages of high mass transfer and efficient utilization of active substances, have recently attracted extensive attention. Herein, two reactive fluorophores (OBP and PIDT) were initially evaluated for detecting the nerve agent simulant, and related sensing mechanisms were manifested comprehensively. Thereafter, two fluorescent bubbles were optimized based on the two doping active fluorophores, possessing long durability over 100 min and fast turn-on response to gaseous analytes. In contrast to the homogeneous detection in droplets, a dramatic 24.9-fold signal amplification capability was observed in the optimized bubble sensors. The term of a high surface area-to-volume ratio, unidirectional gas absorption, and spontaneous analyte enrichment is rationalized principally. Furthermore, a conceptual sensing platform was fabricated for detecting gaseous diethylchlorophosphate (DCP), a nerve agent simulant. Consumption of the stock solution for each detection was minimized to 2.0 μL, with a favorable low detection value of 1.32 ppt for gaseous DCP. Importantly, a binary-component bubble sensor array was composed virtually, and some potential acid interferences like HCl were discriminated based on the acquired multiplexed signals. The present work displays the first fluorescent bubble sensor array for high-performance gaseous detection and a conceptual sensing platform, paving the way for advanced sensing applications.