Facile Design of Label-Free Electrochemical Immunosensor Using AuNPs@ZIF-8@f-MWCNTs for CA-125 Detection in Ovarian Cancer

The early diagnosis of ovarian cancer (OC) is a critical factor in the effective treatment and improved patient outcomes. This study presents a facile design label-free electrochemical immunosensor, a biomarker associated with OC, for high-sensitivity detection of CA-125. Our approach, which involves an immobilization strategy utilizing nanocomposites of gold nanoparticles/zeolitic imidazolate framework-8/carboxylic acid-functionalized multi-walled carbon nanotubes (AuNPs@ZIF-8@f-MWCNTs), has significant potential for the early diagnosis of OC. The synergistic effect of AuNPs, ZIF-8, and f-MWCNTs within the nanocomposites enhances stability, electrical conductivity, and electrochemical signal while providing a large surface area with numerous binding sites for increased Ab loading. When used as electrode material for CA-125 detection, the AuNPs@ZIF-8@f-MWCNTs demonstrate a detection range of 10 to 10⁻⁶ µg/mL with a lower detection limit (LOD) of 1 pg/mL. Our proposed immunosensor shows promise in detecting CA-125 in human serum samples certified as healthy conditions (with a volume of CA-125 < 35 U/mL), endometriosis, and OC conditions that involve CA-125 match well with the hospital results, especially in endometriosis cases, these results showed that our work very sensitivity to detect the CA-125 at a meager value, present a good potential in advance. In addition, in 3 consecutive tests, the relative standard deviation (RSD) was less than 2.5 %, which still displays excellent stability with 2.5% RSD, a crucial factor for early OC diagnosis and a testament to the reliability of our research.