Design and green synthesis of naphthalimide-based organic molecule for non-enzymatic detection of uric acid in solid...

Green synthetic approaches have gained considerable attention as an eco-friendly alternative to conventional methods by reducing toxicity, improving atom economy, and employing environmentally benign solvents. Such approaches enable the development of scalable and cost-effective chemosensors for practical diagnostic applications. Herein, a naphthalimide-based organic molecule, 4-(1,3-dioxo-6-(phenylamino)-1H-benzo[de]isoquinolin-2(3H)-yl)-2-hydroxybenzoic acid [DPIHB] was synthesized in a deep eutectic solvent, providing a scalable and cost-effective route for selective detection of uric acid (UA) in both solution and solid states. Screening of DPIHB against various bioanalytes revealed selective fluorescence enhancement and a bathochromic shift in absorbance exclusively in the presence of UA. Spectroscopic and spectrometric analysis confirmed the formation of a 2:1 (DPIHB-UA) complex, mediated by H-bonding interactions. The molecule exhibited high sensitivity in aqueous medium with a LOD of 0.38 μM and a linear response range of 0-120 μM. Additionally, the excellent stability, reproducibility, and rapid response of DPIHB-coated paper strips underscore its solid-state chemosensing capability. Based on these attributes, a cost-effective prototype kit is proposed for user-friendly, on-site detection of UA, making it suitable for deployment even in remote areas lacking advanced analytical facilities. The consolidated research described herein may provide enormous information for designing point-of-care diagnostic kits for further practical implementation.