Development of a near-infrared fluorescence sensing platform based on TCPP-His@ZIF-8 for highly sensitive...

A novel near-infrared luminescent fluorescent composite material, TCPP-His@ZIF-8, was successfully constructed. Through an amide condensation reaction, Tetrakis (4-carboxyphenyl) porphyrin (TCPP) was covalently anchored onto the surface of L-histidine (His) -modified ZIF-8 metal-organic framework. This material serves as a highly sensitive near-infrared fluorescence sensing platform. Upon introducing mitoxantrone (MITX) as a fluorescence quencher, the material achieves highly selective and sensitive fluorescence detection of MITX. Mechanistic studies revealed that the fluorescence quenching of TCPP-His@ZIF-8 by MITX involves multiple mechanisms: the shift in absorption peaks confirms the presence of static quenching, while FRET is the primary mechanism responsible for the shortening of fluorescence lifetime, i.e., the dynamic quenching process. The inner filter effect (IFE) contributes partially to the reduction in apparent fluorescence intensity but is not the dominant factor. Under optimal experimental conditions, the sensor exhibits good linearity for MITX detection within the range of 0.125-14.0 μM, with a detection limit as low as 91.93 nM. Anti-interference and selectivity experiments demonstrated that common interferents and antibiotic analogues did not significantly affect detection. Furthermore, spiked recovery experiments in real samples such as tap water, milk, and human serum yielded satisfactory results, validating the reliability and potential of this method for practical applications.