Au-TiO2-Al2O3 nanocomposites for multi-analyte detection and plant health monitoring

Aimed to detect water, nutrient, and disease in plants by wearable sensors that operate in ISS or crewed habitat for generic plants with smooth or hairy leaves, we propose to develop a concurrent one-channel multi-analyte detection sensor that is composed of thin-film Au-TiO2-Al2O3 nanocomposites (1-2 cm wide, 1-2 cm long, 10-50 μm thick, suitable for most crop leaves) to simultaneously detect water, ethylene (C2H4), and hexanal (C6H12O) on plant leaves (for concentrations as low as 1 ppm) based on the reversible adsorption, photooxidation (if applicable), and desorption process. This system would enable in situ and non-destructive detection of gaseous molecules of interest by recording real-time changes in electrical resistance of the thin-film sensor when these molecules are adsorbed and desorbed on the nanocomposite. The whole signal recording system will be designed to be miniaturized, easy to calibrate (on Earth and aboard ISS), easy to operate, and wireless (in Phase II). Goeppert will also provide detailed instruction on its calibration, operation, data collection, and artificial intelligence (AI)-driven analysis. Our instrument is designed to (1) enable low-concentration and multiplexed determination of inorganic and organic analytes from the emission of stomates on plant leaves, where more analytes in addition to water, ethylene, and hexanal will be studied after Phase I, and (2) establish a miniaturized, wireless, and AI-driven analytical laboratory for the health monitoring of plants in future ISS and NASA missions. Low-frequency maintenance and self-adjusted calibration also render critical values for space applications to minimize crew time costs. Our innovation will enable smart agricultural and vertical farming which significantly reduces transportation costs of vegetables into ISS and future lunar habitats.