Integration of Metal-Organic Polyhedra onto a Nanophotonic Sensor for Real-Time Detection of Nitrogenous Organic Pollutants in Water

The grave healthand environmental consequences of waterpollutiondemand new tools, including new sensing technologies, for the immediatedetection of contaminants in situ. Herein, we report the integrationof metal-organic cages or polyhedra (MOCs/MOPs) within a nanophotonicsensor for the rapid, direct, and real-time detection of small (<500Da) pollutant molecules in water. The sensor, a bimodal waveguidesilicon interferometer incorporating Rh(II)-based MOPs as specificchemical receptors, does not require sample pretreatment and enablesminimal expenditure of time and reagents. We validated our sensorfor the detection of two common pollutants: the industrial corrosioninhibitor 1,2,3-benzotriazole (BTA) and the systemic insecticide imidacloprid(IMD). The sensor offers a fast time-to-result response (15 min),high sensitivity, and high accuracy. The limit of detection (LOD)in tap water for BTA is 0.068 & mu;g/mL and for IMD, 0.107 & mu;g/mL,both of which are below the corresponding toxicity thresholds definedby the European Chemicals Agency (ECHA). By combining innovative chemicalmolecular receptors such as MOPs with state-of-the-art photonic sensingtechnologies, our research opens the path to implement competitivesensor devices for in situ environmental monitoring.