Electrochemical detection of albumin on a 2D MoS2/WS2-based immunosensor toward sandwich-like formation and [Ru(NH3)6]3+/DNA aptamer signal amplification☆

Human serum albumin (HSA) is a key biomarker linked to various severe health conditions. Abnormal HSA levels in blood serum or urine can signal kidney dysfunction, nephrotic syndrome, liver failure, ischemia, cancer, and other pathologies, leading to the development of a robust, reproducible immunosensor with high sensitivity for accurate HSA assay. This study presents the development of a highly sensitive sandwich-like immunosensor for HSA detection. The sensor is built on a screen-printed carbon electrode modified with a two-dimensional (2D) MoS2/WS2 composite. The biocompatibility of this composite supports the effective immobilization of anti-HSA antibodies without the need for covalent attachment chemicals. HSA quantification was achieved through immunoreactions between antibodies and antigens, where the hexaammine ruthenium (III) cations ([Ru (NH3)6]3+) intercalating within an HSA-specific DNA aptamer chain formed a sandwich-like structure. These [Ru (NH3)6]3+ ions acted as signal amplifiers during the immunoassay, conducted in 0.2 M acetate buffer at pH 4.0 using differential pulse voltammetry. The electrochemical response exhibited a strong linear correlation with the logarithm of HSA concentrations ranging from 1.0 to 200 ng mL- 1 , with a limit of detection of 0.80 ng mL- 1 . Additionally, the immunosensor demonstrated excellent analytical performance, including high reproducibility, sensitivity, selectivity, and stability. Recovery tests using human serum spiked with HSA provided satisfactory results. This proof-of-concept study suggests that the developed immunosensor, incorporating 2D MoS2/WS2 nanocomposite, holds great potential for clinical diagnostics.