Inner filter effect-induced fluorescence quenching via nanoflower like probe for highly sensitive detection of 3-Nitrotyrosine biomarkers in human serum

Sensitive and rapid detection of biomarkers remains a critical challenging task in disease monitoring, diagnosis, and therapeutic intervention. In this study, we developed a nanoflower-structured fluorescent sensor (ZBM) synthesized from Zn 2+ ions coordinated with dual ligands, 2-methylimidazole and 2-aminoterephthalic acid. Given that a lot of diseases such as malignant tumors are often associated with inflammatory responses, the key biomarker 3-nitrotyrosine (3-NT) which would be over-expressed was selected as the target analyte. The RGB values of colorimetric cards could be picked and embedded into a smartphone applet. The ZBM sensor exhibited exceptional responsiveness to 3-NT, demonstrating ultra-fast detection (<10 s), high quenching efficiency, strong anti-interference capability, and a low detection limit (0.59 μM). Theoretical calculations revealed that the selective fluorescence quenching mechanism of ZBM by 3-NT arises from the synergistic effects of photoinduced electron transfer (PET) and inner filter effect (IFE). Furthermore, the practical applicability of this sensor was validated through the determination of 3-NT in real biological samples, achieving satisfactory recoveries ranging from 97.86 % to 105.20 %.