An ultrasensitive 2,4,6-trinitrophenol nanofluidic sensor inspired by olfactory sensory neurons in sniffer dogs

Abstract

Explosives, as high-energy materials, could generate huge destructive explosions along with a massive release of energy. The regulatory or illegal transportation of explosives threatens the peace and stability worldwide. Among the many high-powered explosives, 2,4,6-trinitrophenol (TNP) is not only frequently used in many terrorist attacks, but also seriously jeopardizes environmental safety and human health. Hence, dependable methods for high-sensitivity, rapid and portable detection are desperately needed. Inspired by olfactory sensory neurons (OSNs) in sniffer dogs, we present a nanofluidic sensor for ultrasensitive TNP detection by in situ growing dense UiO-66-NH₂ layers on the surface of anodic aluminum oxide (AAO) nanochannels. TNP could be specifically captured by UiO-66-NH₂ of the sensor through charge transfer to form Meisenheimer complexes, which cause the ionic current change. The TNP concentrations are quantitatively analyzed by monitoring the changed ionic current. And the detection range is from 10⁻¹⁴ to 10⁻¹⁰ g mL⁻¹ with a limit of detection as low as 6.5 × 10⁻¹⁶ g mL⁻¹, which is far beyond those of the state-of-the-art sensors. This work provides a novel strategy for ultrasensitive detection of TNP as well as other explosives, which opens new and promising routes to various breakthroughs in the fields of homeland security, military applications, security inspections and environmental monitoring.