Highly fluorescent nitrogen doped carbon dots as analytical probe for sensitive detection of curcumin through smartphone integrated 3D-printed platform: A new horizon in food safety.

COVID-19 pandemic has significantly influenced the dietary habits of humans, emphasizing the incorporation of natural ingredients to enhance immunity towards viral and bacterial infections. Curcumin (Cur), a widely used traditional medicine in various Asian countries and a natural coloring agent, has gained popularity, leading to surge in its usage specially in post COVID-19 era. This surge has led to increased scrutiny of the potential side effects of excessive Cur use, with recent reports suggesting it may result in inactivation of DNA and reduce adenosine triphosphate levels, leading to health risks. In this work, we synthesized highly fluorescent nitrogen-doped carbon dots with a photoluminescence quantum yield of 72.9 % for the sensitive and selective detection of Cur. The developed fluorescent probe exhibits excellent sensory response towards Cur within a concentration range of 0.081-51.45 µM, achieving an ultra-low detection limit of 15.91 nM. The sensor was successfully tested on real food samples like ginger powder, turmeric powder, and curry powder, demonstrating good recovery rates. To assess the practicality of the sensor system, we developed a 3D-printed smartphone-integrated device platform for curcumin detection through fluorescence image analysis. This developed platform exhibited promising results, achieving a limit of detection (LoD) of 132.28 nM across a curcumin concentration range of 0.13-54.00 µM. This device platform holds significant potential for the development of efficient sensors for real-time detection of Cur in food samples.