Electrochemical aptasensor based on a dual signal amplification strategy of 1-AP-CNHs and ROP for highly sensitive detection of ERα.

Estrogen receptor alpha (ERα) serves as a crucial biomarker for early breast cancer diagnosis. In this study, we proposed an electrochemical aptasensor with nanomaterial carbon nanohorns/gold nanoparticle composites (1-AP-CNHs/AuNPs) as the substrate, and the primary amine groups on the antibody initiated the ring-opening polymerization (ROP) of monomer amino acid-ferrocene (NCA-Fc) on the electrode surface for ultrasensitive detection of ERα. The composite of 1-AP-CNHs/AuNPs not only possessed more active sites, but also increased the specific surface area of the electrode and allowed a large amount of ferrocene polymer long chains to be grafted onto the electrode surface to achieve signal amplification. Under optimal conditions, the detection limit of the method was 11.995 fg mL with a detection range of 100 fg mL-100 ng mL. In addition, the biotin-streptavidin system was used to further improve the sensitivity of the sensor. Importantly, this approach could be applied for the practical detection of ERα in real samples.