In situ growth of MoS2 on MOF-derived ZnSe-FeSe2 for enhanced charge transfer toward electrochemical immunosensing of the ovarian cancer biomarker CA-125.

Ovarian cancer (OC) is one of the deadliest gynecological cancers, primarily because of the lack of effective techniques for early detection. The precise detection of cancer antigen 125 (CA-125), a well-known biomarker of OC, is vital for early diagnosis. In this study, we developed a novel electrochemical immunosensor based on flower-like ZnSe-FeSe2@MoS2 for highly sensitive detection of CA-125. First, a ZnSe-FeSe2 nanocomposite was synthesized via the thermal annealing of iron-doped zeolitic imidazolate framework-8 (Fe-ZIF-8) with selenium powder. Subsequently, the flower-like ZnSe-FeSe2@MoS2 was obtained through the solvothermal growth of MoS2 in the presence of varying amounts (20-100 mg) of ZnSe-FeSe2 material. The structural and morphological features were analyzed using spectrophotometric methods, and the electrochemical properties were assessed via voltammetry and impedimetry. Among different concentrations tested, ZnSe-FeSe2(80)@MoS2 exhibited the optimum electrochemical performance. The immunosensor was fabricated by modifying a glassy carbon electrode (GCE) with ZnSe-FeSe2(80)@MoS2, followed by the immobilization of Ab-CA-125 using chitosan (CS) and glutaraldehyde (Glut) as crosslinking agents. The resulting sensor (BSA/Ab-CA-125/Glut/CS/ZnSe-FeSe2(80)@MoS2/GCE) demonstrated a broad linear detection range spanning 1 × 10-6 to 1 × 103 U mL-1 and an extremely low detection limit of 4.68 × 10-8 U mL-1. Additionally, it demonstrated excellent stability and reproducibility, along with reliable recovery rates in human serum samples. These results indicate that the ZnSe-FeSe2@MoS2-based electrochemical immunosensor is a promising candidate for the early and accurate diagnosis of OC.