Novel competitive SERS/Electrochemical dual-channel biosensor for ultrasensitive quantitative detection of Pb2+ based on Fe3O4@Au@PAMAM and AuNs@4-MBA@Au

In this paper, a SERS/electrochemical dual-channel aptamer biosensor was established for ultrasensitive detection of Pb 2+ . Firstly, the capture probe Fe 3 O 4 @Au@PAMAM@Aptamer and the signal probe AuNs@4-MBA@Au@ssDNA were chemically synthesized step by step. Secondly, the carboxyl graphene oxide (GO) was electrodeposited onto the electrode surface to gain the GO/SPCE. Meanwhile, PAMAM@Au nanomaterials were successfully synthesized and thus prepared the Aptamer/PAMAM@Au/GO/SPCE. During the process, SEM, TEM, FTIR and XPS were applied to characterize the synthesized nanomaterials which confirmed the successful synthesis of the nanomaterials. Finaly, the performance of this biosensor was evaluated in a series of Pb 2+ aqueous solutions by surface enhanced Raman (SERS) and differential pulse voltammetry (DPV). The results showed that the lowest limit of detection (LOD) was 3.16 × 10 −5 nM, and the sample recovery was 99.50–103.67 %. Furthermore, the biosensor demonstrated good specificity, repeatability, and stability. Reliable results were also obtained in actual sample testing. Therefore, it can provide a viable method for trace detection of heavy metal ions.