A dual-signal electrochemical aptasensor based on rGO@MoS₂-Fc nanozyme for sensitive detection of low-density...

Cardiovascular disease (CVD) is the leading cause of death worldwide, particularly in the developing countries. Low-density lipoprotein (LDL), a critical biomarker for the early detection and intervention of CVD, provides valuable diagnostic and prognostic information for CVD. Herein, we developed a dual-signal electrochemical aptasensor for LDL detection based on a peroxidase-like nanozyme composed of reduced graphene oxide@molybdenum disulfide-ferrocenecarboxylic acid (rGO@MoS₂-Fc). In the process of electrochemical testing, rGO@MoS₂-Fc achieved the synergistic amplification of electrochemical signals both an enhanced Fc oxidation current detected by differential pulse voltammetry (DPV), and an increased hydrogen peroxide (H₂O₂) decomposition current via amperometric current-time (i-t) analysis. The DPV signal, corresponding to Fc oxidation, exhibited a logarithmic linear response over a broad LDL concentration ranged from 0.001 to 100.0 μg/mL, with a limit of detection (LOD) as low as 0.91 ng/mL. Meanwhile, the i-t signal, arising from H₂O₂ decomposition, displayed a linear range of 1.0 to 80.0 μg/mL and an LOD of 0.80 μg/mL. This dual-signal strategy exhibited good selectivity, reproducibility, stability and self-calibration capability. Analysis of human serum samples showed that the proposed strategy is expected to be a powerful method for early-stage CVD diagnosis and clinical management.