A synergistically enhanced electrochemiluminescent aptasensor based on antenna effect and localized surface plasmon...

Chloramphenicol (CAP) is a serious antibiotic residue in milk that poses health risks to consumers, prompting the exploration of exceptionally responsive diagnostic techniques such as electrochemiluminescence (ECL). Lanthanide-based coordination polymers exhibit promising ECL via the intrinsic antenna effect, yet they suffer from low radiative decay rates and high non-radiative transition probabilities, thereby limiting their analytical sensitivity. To overcome these drawbacks, we report a dual-enhancement strategy that synergistically combines the intrinsic antenna effect of a europium porphyrin coordination polymer (Eu-PCP) with the extrinsic plasmonic resonance (LSPR) behavior triggered by silver nanostructures (Ag NPs), where the Ag NPs-derived LSPR boosts the surrounding electromagnetic environment to accelerate the radiative decay of excited Eu-PCP via the purcell effect, while the antenna effect ensures efficient energy transfer to Eu³⁺ centers. A flower-like mesoporous Eu-PCP was synthesized and served as both the ECL emitter and aptamer immobilization substrate. Ag NPs functionalized with complementary DNA (cDNA) were hybridized with the aptamer, bringing the Ag NPs into close proximity to Eu-PCP, which dramatically amplifies the ECL signal via enhanced radiative decay, rendering an ECL intensity amplification of 5.2 times. For chloramphenicol (CAP) detection, the aptasensor exhibits an ultrawide linear range from 1 × 10^-15 to 1 × 10^-7 mol/L, a detection threshold as low as 4.79 × 10^-16 mol/L, and outstanding specificity, reproducibility, and stability. This study successfully establishes a dependable framework for monitoring antibiotic residues in food while simultaneously offering a new paradigm for designing high-performance ECL sensors through synergistic integration of intrinsic and extrinsic enhancement mechanisms.