A Turn-on Fluorescent Sensor Based on Copper-Based Metal-Organic Frameworks for Sensitive Detection of L-Histidine

As an important amino acid in the body, L-histidine participates in various physiological processes. Therefore, it is of great necessity to establish a rapid and effective method for L-histidine sensing, especially in blood and urine. In this work, a fluorescence sensor for detection of L-histidine was successfully developed using Cu-MOFs/Fe[Formula: see text] sensor. Cu-MOFs with blue emission served as the identification unit and signal source, and Fe[Formula: see text] played the role of “quencher” in this system. Fe[Formula: see text] induced the fluorescence quenching of Cu-MOFs to form Cu-MOFs/Fe[Formula: see text] sensor due to the effect of photoinduced electron transfer (PET). After the addition of L-histidine, Fe[Formula: see text] was captured by L-histidine to form L-histidine-Fe[Formula: see text] complex, which inhibited the PET effect from Cu-MOFs to Fe[Formula: see text], resulting in the fluorescence recovery of Cu-MOFs. With such a design, L-histidine detection was realized with a wide linear range from 1[Formula: see text][Formula: see text]M to 190[Formula: see text][Formula: see text]M. The limit of detection (LOD) was calculated as low as 0.156[Formula: see text][Formula: see text]M. In addition, successful detection of L-histidine in blood serum with high selectivity and sensitivity indicated the real applications and potential diagnostic value of Cu-MOFs/Fe[Formula: see text] system.