Biobased carbon quantum dots: An emerging nano-enabled paradigm for pesticide removal and sustainable plant protection

Owing to their tunable surface chemistry, high biocompatibility and unique optical properties, carbon quantum dots (CQDs), nanoscale carbon particles, are emerging as multifunctional agents for plant protection. This review critically explores how the physicochemical properties of CQDs, especially those synthesized from green precursors, modulate plant responses to diverse stressors. CQDs help plants handle stress better by balancing reactive oxygen species (ROS), increasing the expression of defense-related genes, and improving cellular functions. Current evidence from this review indicates that CQDs mitigate abiotic stressors such as drought, heavy metals, chemicals, salinity, heat, and UV light while also suppressing biotic threats, including pathogens (fungi, bacteria, nematodes, viruses, oomycetes), insects, and weeds. Additionally, when CQDs are used with other nanofertilizers, they appear to improve soil microbes and lower soil toxicity. Despite these advances, challenges, such as toxicity thresholds, field scalability and regulatory gaps, persist. Future work should prioritize the structure-function optimization of CQDs and their integration into sustainable agricultural frameworks.