One-step synthesis of molecularly imprinted fluorescent sensors for highly selective detection of nicotinamide mononucleotide

A one-step approach was employed to synthesize fluorescent molecularly imprinted polymers (MIP@QDs) using CdSe quantum dots modified with sulfhydryl groups as the fluorescent core. Nicotinamide mononucleotide (NMN) was utilized as the template, methacrylic acid served as the functional monomer, and N,N′-methylenebisacrylamide functioned as the crosslinker for precipitation polymerization. Fluorescence quenching of the MIP@QDs enabled the quantitative detection of NMN. Within the concentration range of 0–100 µg·mL⁻¹, the fluorescence intensity of the MIP@QDs decreased with increasing NMN concentration, with a detection limit of 0.0692 µg·mL⁻¹. The MIP@QDs displayed superior selectivity for NMN compared with its structural analogues. Furthermore, application of the MIP@QDs to actual broccoli samples resulted in an NMN recovery rate ranging from 93.25 to 96.20%, with a relative standard deviation of 3.65–4.55%. This study provides a method for the facile preparation of fluorescent sensors based on precipitation polymerization, enabling rapid identification and quantification of NMN in complex matrices.