Executive Summary : | The widespread use of persistent carcinogenic and cytotoxic pesticides has infiltrated the food chain through air, water, and soil, causing considerable harm to human and animal health. Particularly, table grapes are a commodity that is heavily consumed globally and is heavily sprayed with pesticides. There is a need to research the applicability and efficiency of a simple method for on-site detection of chosen fungicides such as Flusilazole and Tebconazole. The pesticides/fungicides (target analytes) were chosen based on CIB&RC recommendations, popular usage, and residue identified in grapes. The current generation of pesticide residue detection technologies (HPLC, GC, LC-MS/MS, GC-MS/MS) have several limitations such as expensive instrumentation, difficult sample preparation and purification procedures, and no recognised way to detect and quantify combined pesticides. Since the 1970s, quantum excitons and nanoparticles have been preferred over fluorescent dyes in biosensors due to their unique electronic, mechanical and optical properties. They have large surface-to-volume ratios, low photobleaching, and unusual target binding characteristics. Our research will use unique optical features of Cd-free metal oxide QDs and nanoparticles for ultrasensitive and multiplex optical detection of pesticides/fungicides. To make our sensor more stable and sensitive to specific targets, we will combine plasmonic effects into QDs/nanoparticles made of gold, silver, etc. Determining the presence of pesticides/fungicides in real samples (grapes) while avoiding autofluorescence interference and photobleaching is our goal. The high sensitivity of QDs/nanoparticles luminescence, along with plasmonic effects on their surface state, is being used to develop fluorescence transduction. Chemical or physical interactions at the surface of QDs change the efficiency of radiative recombination, either activating or quenching photoluminescence (turn-off). Direct contact between analyte and QD/nanoparticle surface, unmodified or functionalized with a particular ligand, has enabled selective detection of a wide range of chemicals. Our study will use surface coordination-derived FRET of metal oxide QDs/nanoparticles and a simple ligand-replacement fluorescence turn-on/turn-off mechanism to detect pesticides/fungicides without enzymes. Metal oxide QDs and nanoparticles are now frequently used in sensors to improve selectivity and sensitivity for targets like proteins, poisons, and bio-related small chemicals. The current proposal aims to create highly photostable, biocompatible, and selective fluorometric pesticide sensors that can not only detect single pesticides but also measure pesticide mixtures. As a result, our project will enable us to develop a new nanosensor that can detect and degrade toxic pesticide residues and their derivatives in/from grape samples. |