Graphene Quantum Dot Based Fluorescent Nanozyme for Sensitive Detection of Nicotinamide Adenine Dinucleotide Phosphate (NADPH)

Nanozymes are nanomaterials that display enzyme-like properties for catalysis of reactions and principal components. The advantageous features of nanozymes include low production cost, high catalytic activity, and ease of generating modifications. Graphene dots, due to their unique optical and electronic properties hold significant potential for sensing applications. Their small size and high surface area-to-volume ratio allow for efficient catalytic activity and enhanced sensitivity. NADPH, a target of metabolism functions as a reducing agent in many biosynthetic and antioxidant reactions in cells. Accurate and sensitive detection of NADPH is crucial for studying its role in cellular processes, diagnosing and monitoring diseases such as cancer, neurodegenerative disorders, and metabolic diseases. In this work, new graphene quantum dots (Fe-N4-GQDs) were synthesized using hemin and polyethyleneimine under 200 °C for 15 hours. The optical properties, morphology, and functional groups of the newly synthesized graphene quantum dots were systematically characterized by analytical spectroscopy methods. Results showed that Fe-N4-GQDs have an excitation and emission peaks of 360nm and 460nm, respectively. These properties demonstrate their potential use for the detection of NADPH.