Eu(III)-Functionalized MOF-Based Dual-Emission Ratiometric Sensor Integrated with Logic Gate Operation for Efficient Detection of Hippuric Acid in Urine and Serum.

ABSTRACT

With the introduction of Eu3+ ions as the secondary fluorescent signal reporter and sensing active sites, a dual-emission ratiometric sensor of Eu3+@NiMOF (Eu3+ functional NiMOF) for hippuric acid (HA) detection in urine and serum was fabricated via the postsynthetic encapsulating strategy. Based on the two emission signals at 441 nm (turn-on) and 628 nm (turn-off), the produced Eu3+@NiMOF ratiometric sensor provided enhanced sensitivity, higher selectivity, and 9.7 times lower limits of detection (LOD) for the detection of HA (2.38 µM, 0.42 µg·mL-1) than that of the pristine NiMOF. Considering the high sensitivity and visualization results, further exploration of intelligent applications in the HA sensing process was carried out by constructing a tandem combinational logic gate to improve the practicability and convenience with the help of a smartphone. This work provides a promising approach for developing MOF-based ratiometric sensors to detect biomarkers.