Grant: Idea to Innovation

We will develop an integrated ultra-compact chemical sensor system that is suitable for ppb- to ppm-level detection of common contaminants in water and air. Initial targets are the heavy metal ions lead, Pb(II), and mercury, Hg(II) in groundwater and surface water. The same sensor platform will also be used for sensing of volatile organic compounds (VOCs) and initially we will focus on BTEX (benzene, toluene, ethylbenzene and xylene) as a contaminant class that is indicative of poor indoor air quality. In a departure from previously developed chemical sensor platforms we will use micro-photonic devices, in particular micron-sized interferometers and ring-resonators, as a versatile sensing platform. Micro-photonic devices are fabricated on silicon wafers using a process analogous to that of electronic integrated circuit microfabrication. They can be easily multiplexed to form sensor arrays with a density of hundreds of different sensors per square centimeter. While robust and reproducible production protocols of these micro-photonic sensor array chips are gradually emerging, their use a chemical sensors is presently hampered by inadequate chemical recognition on the sensor surface. Using new classes of coatings developed by the PIs in combination with custom designed micro-photonic devices and new interrogation methods, we will overcome this barrier. In another departure of previously developed biosensors based on micro-photonic devices, we will develop coatings that show strong but reversible binding to the targeted analyte under ambient environmental conditions. In preliminary experiments, the Queen's researchers found that the coatings previously used for gas sensing and for sensing of heavy metals have the potential of fully reversible but strong chemical binding, thereby opening the possibility of an ultra-compact sensor of environmental (indoor and outdoor) contaminants or water and air at ambient concentrations.