Nanosensors for hazardous pesticides and nanofertilizers for sustainable agricultural: Contribution of carbon quantum dots

The increasing global population threatens food security, necessitating sustainable agricultural practices. Intensive farming has led to the excessive use of pesticides and fertilizers, contaminating soil and water sources causing the impairment of the environment. Pesticide residues enter the food chain, posing serious health risks like neurotoxicity, genetic mutations, and diseases such as Alzheimer's, Parkinson's, diabetes, etc. Conventional detection methods are costly, complex, time- consuming, unsuitable for onsite detection, and mostly are not eco-friendly. Fluorescent-based nano-biosensors, particularly carbon quantum dots (CQDs), offer a promising alternative to detect pesticides and herbicides due to their high sensitivity, biocompatibility, low toxicity, and photostability. In addition to its sensory application, CQDs could be used as an alternative to conventional chemical fertilizers for crop production. CQDs-based nano fertilizers improve nutrient absorption, boost plant growth, and increase resistance to environmental stressors. This review will highlight the key advancements of CQDs in terms of various synthetic techniques and their usage as nanosensors and nano fertilizers.