Development of a Green-Synthesized WA-CDs@MIL-101 Fluorescent Sensor for Rapid Detection of Panax notoginseng Leaf Pathogen Spores

The leaf diseases of <i>Panax notoginseng</i> (<i>Panax notoginseng</i> (Burk) F. H. Chen) are mainly spread by spores. To enable rapid and sensitive detection of spores for early warning of disease spread, we developed a carbon dot-based fluorescent probe encapsulated by MIL-101 using wax apple as a green carbon source (WA-CDs@MIL-101). The WA-CDs@MIL-101 was thoroughly characterized, and the detection conditions were optimized. The interaction mechanism between WA-CDs@MIL-101 and spores was investigated. The fluorescence of WA-CDs@MIL-101 was recovered due to electrostatic adsorption between spores and WA-CDs@MIL-101. Under the optimized detection conditions, the probe exhibited excellent sensing performance, showing a strong linear relationship (<i>R</i>² = 0.9978) between spore concentration (0.0025-5.0 mg/L) and fluorescence recovery ratio, with a detection limit of 5.15 μg/L. The WA-CDs@MIL-101 was successfully applied to detect spores on <i>Panax notoginseng</i> leaves, achieving satisfactory recoveries (94-102%) with relative standard deviations of 1.3-3.4%. The WA-CDs@MIL-101 shows great promise for detecting spores on <i>Panax notoginseng</i> leaves.