A Sensitive Electrochemical Aptasensor for Mucin 1 Detection Based on Catalytic Hairpin Assembly Coupled with PtPdNPs Peroxidase-like Activity

In this work, an ultrasensitive aptasensor for the detection of Mucin 1 (MUC1) was presented based on the target-induced catalytic hairpin assembly combined with excellent mimic peroxidase performance of PtPd bimetallic nanoparticles (PtPdNPs). Traditionally, the cyclic reuse of target protein was achieved by protein conversion with enzyme cleavage or polymerization, which is costly and complex. However, in this work, it can be performed by simple strand displacement. In addition, PtPdNPs, a mimic peroxidase, was used a probe to catalyze the oxidation of tetramethylbenzidine (TMB) by HO, leading to the electrochemical signal amplification. With this ingenious design, the prepared aptasensor for MUC1 detection showed a favorable linear response from 100 fg mL to 1 ng mL and a relatively low detection limit of 16 fg mL. The proposed biosensor possessed acceptable stability, selectivity and reproducibility for MUC1 assay. Additionally, the fabricated aptasensor has been successfully applied to detect MUC1 in serum samples with satisfactory results. This new strategy supplied one efficient approach to improve signal amplification, which also open an avenue for sensitivity enhancement in targets detection.