An Efficient Electrochemiluminescence Biosensor Based on Ru(bpy)₃²⁺@AuNPs@SWCNTs for miRNAs Detection Using a Dual Engine-Triggered DNA Walker

The diagnosis and treatment of acute pancreatitis remain challenging due to the limitations of diagnostic methods, which often result in delayed treatment and suboptimal outcomes. This underscores the need for innovative diagnostic strategies to enable early detection and improve therapeutic interventions. Electrochemiluminescence (ECL)-based biosensors have emerged as a promising solution, offering advantages such as cost-effectiveness, ease of use, and high sensitivity. This study introduces an innovative ECL biosensor design, which incorporates a DNA tetrahedron as a structural scaffold, a double swing arm mechanism for enhanced motion control, and a track-based signal regulation system. This design significantly enhanced the operating efficiency and controllability of DNA walkers. The system utilizes ferrocene (Fc) as a signal quenching agent, with its electrochemical signal restored upon interaction with miRNA24-3p, a biomarker for acute pancreatitis. The platform features a composite luminescent material─tris(2,2'-bipyridine) dichlororuthenium(II)@goldnanoparticles@single-walled carbon nanotubes (Ru(bpy)₃²⁺@AuNPs@SWCNTs)─and employs persulfate as a coreactant. Under optimized conditions, this design demonstrated a wide dynamic range (10^-15 M to 10^-6 M) and an ultralow detection limit of approximately 60 aM for miRNA 24-3p. Additionally, it exhibited excellent specificity, reproducibility, and stability. These findings underscore the potential of this application of this ECL-based platform to revolutionize the clinical diagnosis of acute pancreatitis by enabling more timely and accurate interventions while paving the way for advancements in diagnostic technologies.