Nanocatalytic Interface to Decode the Phytovolatile Language for Latent Crop Diagnosis in Future Farms

Abstract

Crop diseases cause the release of volatiles. Here, the use of an SnO 2 -based chemoresistive sensor for early diagnosis has been attempted. Ionone is one of the signature volatiles released by the enzymatic and nonenzymatic cleavage of carotene at the latent stage of some biotic stresses. To our knowledge, this is the first attempt at sensing volatiles with multiple oxidation sites, i.e., ionone (4 oxidation sites), from the phytovolatile library, to derive stronger signals at minimum concentrations. Further, the sensitivity was enhanced on an interdigitated electrode by the addition of platinum as the dopant for a favorable space charge layer and for surface island formation for reactive interface sites. The mechanistic influence of oxygen vacancy formation was studied through detailed density functional theory (DFT) calculations and reactive oxygen-assisted enhanced binding through X-ray photoelectron spectroscopy (XPS) analysis.

Sensing nature's alarm: SnO2/MXene gas sensor unveils methyl jasmonate signatures of plant insect stress

“…Therefore, in recent times, several initiatives have emerged to create sensors aimed at identifying different stresses in plants by leveraging the unique signatures of volatile organic compounds (VOCs), drawing inspiration from health science. [3][4][5] Detecting VOCs under ambient circumstances is time-consuming as it depends on methods like gas chromatography, mass spectrometry, and fluorescence spectroscopy, which need sophisticated pre-concentration steps. [6][7][8][9][10] Chemoresistive sensors present a potential remedy for this concern, as their function is based on the alteration of their electrical resistance upon exposure to specific gases or chemicals in their environment.…”

Handheld Crop Pest Sensor Using Binary Catalyst-Loaded Nano-SnO2 Particles for Oxidative Signal Amplification

“…The challenge in the detection of these signature molecules is their very low concentration. In our previous demonstration, the signature molecule with multiple oxidizing sites were chosen to tap readable signals in the detection of crop diseases . For the first time, here, a bimetallic catalyst that can oxidize the target molecule, as well as its subsequent products is attempted to improve the signal from a trace amount of phyto-volatile.…”

“…In our previous demonstration, the signature molecule with multiple oxidizing sites were chosen to tap readable signals in the detection of crop diseases. 34 For the first time, here, a bimetallic catalyst that can oxidize the target molecule, as well as its subsequent products is attempted to improve the signal from a trace amount of phyto-volatile. To the best of our knowledge, only a handful of studies have explored bimetallic catalysts for the chemoresistive sensor, which includes AuPd nanoparticles (NPs) in SnO 2 for aldehyde and acetone; 35 Pt/Pd core−shell NPs in SnO 2 for CO and methane; 36 PdRu NPs in SnO 2 for trimethylamine; 37 PdO x CuO x -loaded WO 3 for mercaptan; 38 and PdFe in SnO 2 for CO 32 detection.…”

“…The next step was to optimize the doping percentage and thickness of Fe/Pt-doped SnO 2 nanoparticle coating on the electrode for the maximum response. Our previous experience with the Pt doping led us to keep Pt at 0.5 mol % 34 and change the Fe concentration from 0.25 to 1.0 mol % atom. In this study, 0.5 mol % Fe doping gave the maximum response (Figure 3c).…”

“…Based on their environment, the volatiles emitted by the plants differ; hence, such non-target molecules released can also interfere with the sensor response, which may mislead the prediction. To detect β-myrcene selectively, the sensor should be insensitive to other molecules like β-ionone, β-caryophyllene, and ocimene, which are predominantly released from the microbial stress, 34 abiotic stress, 65 and attract beetles for pollination, 66 respectively. Also, the sensor has been found to be less sensitive to methyl jasmonate released during pest infestation.…”