Quantum dots‐based fluorescence immunoassay for detection of tiamulin in pork

Abstract

Tiamulin (TML) is a kind of diterpenoid veterinary antibiotic. If abused, it will cause residues in edible tissues of animals and endanger human health. Thus, a facile, sensitive, and accurate method is essential for TML detection. In this study, TML complete antigen was synthesized by oximation and active ester method, and monoclonal antibodies with high specificity and sensitivity were prepared. ZnCdSe/ZnS quantum dots (QDs) coupled with goat anti‐mouse IgG were used as a fluorescence detection probe to establish indirect competitive fluorescent immunosorbent assay (icFLISA) for the determination of TML in pork. The 50% inhibitory concentration (IC50) of the icFLISA was 0.069 ng/ml, and the limits of detection (LOD) were 0.309 pg/ml. The recovery of the spiked pork samples for the icFLISA ranged from 85.6 to 96.8%, and the coefficient of variation (CV) was less than 9.4%. The results showed that the icFLISA based on ZnCdSe/ZnS QDs was more sensitive than the traditional indirect competitive enzyme‐linked immunosorbent assay for the detection of TML in edible animal tissues.

Portable Plasmonic Paper-Based Biosensor for Simple and Rapid Indirect Detection of CEACAM5 Biomarker via Metal-Enhanced Fluorescence

“…Generally, the luminescence peak position of CdSe/ZnS core/shell QD is usually determined by the band gap of CdSe, and it is not affected by its hydrodynamic size or ligands [ 34 ]. Moreover, the fluorescence intensity of the QD@Ab complex is slightly lower than that of free QD, which may be caused by the dilution of QD in the reaction process, or due to loss in the centrifugation step [ 35 ]. Still, no shift was found in the maximum emission peak compared with that of the free QD, which suggests that the coupling of antibodies did not change the luminescence properties of the QD.…”

“…Still, no shift was found in the maximum emission peak compared with that of the free QD, which suggests that the coupling of antibodies did not change the luminescence properties of the QD. Several studies have also shown that the covalent binding of antibodies to QD using NHS/EDC chemistry does not significantly alter their luminescence properties [ 35 , 36 ]. To gain better insight into the behavior of the QD in presence and absence of the antibodies, we investigated the changes in the QD-excited state lifetime, by acquiring and analyzing the fluorescence lifetime images of free QD ( Figure 4 b) and the QD@Ab ( Figure 4 c) complex grafted onto the paper fibers under a fixed excitation wavelength of 405 nm.…”