A Programmable Dynamic Range Electrochemiluminescence Platform with Dual-Signal Output and Single Luminophore, Utilizing Polyadenine-Anchored Triblock DNA

Rational design of nucleic acid capture probes to modulate binding affinity is a valuable strategy for programing the dynamic range and limit of detection (LOD) in electrochemiluminescence (ECL) assays. Current strategies, however, have scarcely achieved this expectation. We present a binding affinity-driven, dynamic range, and LOD programmable triblock DNA-based dual-signal ECL platform for the nucleic acid assay. The probe architecture features a polyadenine (polyA) sequence that positions two flanking, partially complementary strands on a gold electrode with their lateral spacing precisely engineered to regulate target binding affinity. Remarkably, this system generates a dual-signal output from a single ECL luminophore─tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)₃²⁺)─where target-induced conformational changes alter the Ru(bpy)₃²⁺ distance from the electrode surface, thereby triggering distinct ECL generation mechanisms at separate electrochemical potentials. And this dual-signal output enables ratiometric or multi-target assays. This integrated platform features programmable dynamic range and LOD, single recognition element, and dual-signal output with single ECL luminophore, potentially presenting a new approach to advanced ECL nucleic acid sensing platforms.