A “signal off” aptasensor based on AuNPs/Ni-MOF substrate-free catalyzed for detection Enrofloxacin

In this project, we developed an electrochemical aptamer sensor based on the coordinated catalysis toward thionine (Thi) of nickel metal-organic framework (Ni-MOF) and gold nanoparticles (AuNPs) to sensitively detect the enrofloxacin (ENR), which belonged to a third-generation quinolone antibiotic for treat diseases caused by bacteria. In order to improve the analytical performance of the sensor, Ni-MOF and gold AuNPs, as the substrate material, could increase the load of the aptamer (Apt) and synergistically catalyze thionine (Thi). Therefore, ultrathin sheets of gold triangular nanosheets (AuTNSs) were prepared as signal labeling materials, which were loaded with a large amount of Thi and complementary deoxyribonucleic acid (cDNA). With the help with Ni-MOF and AuNPs catalysis toward Thi, under optimal conditions, the aptasensor exhibited a massive detection range of 1×10−2 pg·mL−1 to 1×103 pg·mL−1 (S/N = 3) and a detection limit of 5.6×10−3 pg·mL−1 for ENR. Meanwhile, the proposed sensor has a high sensitivity, satisfactory repeatability and long-time stability, and could be well applied to the detection of food samples.