Detection of prostate specific antigen using a magnetic sulfonated reduced graphene oxide/gold nanoparticle aptasensor

Prostate-specific antigen (PSA), is a protein produced by cancerous cells in the prostate gland, and its presence may indicate the likelihood of prostate cancer. For the purpose of detecting PSA, an innovative aptasensor utilizing magnetic sulfonated reduced graphene oxide/gold nanoparticles was developed. This unique nanocomposite has been used for the first time for biosensing of prostate cancer which resulted in significant enhancement of the biosensor’s performance. Unlike previous works, our biosensor incorporates two detection modes: a label-free detection mode in ferrocyanide solution and a labeled mode using methylene blue. Different tests such as FTIR, XRD and TEM were applied to recognize the characterization of the nanoparticles and to make sure of the linkage of particles. To examine the aptasensor at various stages, a range of electroanalytical techniques, such as cyclic voltammetry (CV), square-wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS), were employed. The aptasensor exhibited significant selectivity for PSA, as demonstrated by its ability to distinguish PSA from other components like glucose, carcinoembryonic antigen (CEA), etc. Ultimately, the detection limit (LOD) reached 1.371 ng/mL in the ferrocyanide environment with an R² value of 0.9777. Furthermore, the labeled electrode in phosphate buffer achieved the remarkable detection limit of 1.566 pg/mL with an R² value of 0.9676 and linear range of 2.5–12.5 pg/mL, demonstrating the impressive sensitivity and accuracy of the method.