A novel electrochemical immunosensor for ultrasensitive detection of CA125 in ovarian cancer

In the current study, we report on the design and development of a novel electrochemical immunosensor for the detection of cancer antigen 125 (CA125) oncomarker. Polyamidoamine/gold nanoparticles (PAMAM/AuNPs) were used to increase the conductivity and enhance the number of antibodies (Abs) immobilized on the electrode surface. Three-dimensional reduced graphene oxide-multiwall carbon nanotubes (3DrGO-MWCNTs) were used to modify the glassy carbon electrode to improve the electrode conductivity and specific surface area. Ab and toluidine blue attached to O-succinyl-chitosan-magnetic nanoparticles (Suc-CS@MNPs) as a tracer. The poor solubility of chitosan (CS) was improved by succinic anhydride using a novel modification method. Under optimum condition, the developed immunosensor exhibited a wide linear range (0.0005–75 U/mL) and an excellent limit of detection around 6 μU/mL. The reliability of the engineered immunosensor in detecting CA125 was verified by standard addition recovery method, which was further compared to enzyme-linked immunosorbent assay (ELISA). The proposed immunosensor exhibited excellent stability, high selectivity and sensitivity, and good reproducibility. Based on the great performance of the engineered immunosensor, it is proposed as a robust and reliable diagnostic tool for the detection of CA125 in the clinic. [Display omitted] •An immunosensor was developed for detecting CA125 with a wide linear range (0.0005–75 U/mL) and an excellent LOD (6 μU/mL).•PAMAM/AuNPs were synthesized through a one-step method using PAMAM as a stabilizing and reducing agent.•Chitosan water solubility in natural pH was increased using a novel modification method.•Succinyl-chitosan-coated magnetic nanoparticles were synthesized with good dispersity and high surface functional groups.