Electrochemical Aptasensor Based on Metal-Organic Framework-derived Bimetallic Materials as Signal Amplifying Elements for Sensitive Detection of Human Epididymis Protein 4

Human epididymis protein 4 (HE4) is recognized as a pivotal biomarker for ovarian cancer, and its accurate quantification in serum is critical for early clinical diagnosis. In this work, an electrochemical aptasensor for detection of HE4 based on a signal amplification strategy utilizing a core-shell structured bimetallic metal-organic framework composite (Zr-MOF-on-Ni-MOF) was developed. Firstly, the electroactive material polyaniline (PANI) was chemically immobilized onto the surface of the Zr-MOF-on-Ni-MOF to form ZNP nanocomposite. Subsequently, gold nanoparticles (AuNPs) were uniformly anchored onto the ZNP surface via Au-N bonds and conjugated with HE4 binding aptamer Ⅱ (Apt Ⅱ), generating a novel tracer label (ZNP/Au-Apt Ⅱ) to enhance electrochemical signal output. Simultaneously, a biotinylated aptamerⅠ (Apt Ⅰ) was immobilized onto the sensing interface modified with a streptavidin-coated Dp Au layer, thus constructing an amplification platform for signal enhancement further. Ultimately, a sandwich-type aptasensor was successfully constructed. Benefiting from the synergistic signal amplification effects of Zr-MOF-on-Ni-MOF and AuNPs nanocomposites, the proposed aptasensor exhibited a wide linear range (1 fmol/L–10 nmol/L) and a low detection limit (0.32 fmol/L). The aptasenor also exhibited good selectivity and stability. This work presented a promising electrochemical strategy for sensitive detection of HE4 and held potential for early clinical diagnosis of ovarian cancer.