SERS sensor combined with the dual DNA cycling amplification assay for the sensitive detection of antibiotic resistance gene in environmental samples

Antibiotic resistance genes (ARGs) have emerged as new environmental pollutants, and even minute quantities of them can seriously affect the environment. Thus, it is urgently required to test trace ARGs. Herein, a surface-enhanced Raman scattering (SERS) sensor based on the dual cycling amplification has been developed for the ultrasensitive detection of bla-TEM. First, the capture DNA on the surface of magnetic beads and the Hg2+ aptamer-based capture strand could achieve the capture, separation, and enrichment of the bla-TEM from the relatively complex samples. Then, the dual amplification process was finished under the catalysis of the enzymes, and the entire process was operated in one step under the isothermal condition. Finally, the enriched SERS nanoprobes were obtained via the feasible magnetic separation and provided Raman signals for the detected bla-TEM under the laser irradiation. Under the optimum experimental conditions, the sensor exhibited excellent sensitivity and good selectivity, obtaining a linear range of 0.1 zM-300 aM and a limit of detection (LOD) of 0.02 zM. It can be successfully used to measure bla-TEM in actual environmental samples, which was in good accordance with the conventional polymerase chain reaction (PCR) analysis, showing great promise for detecting trace ARGs in the environmental samples.