Efficient SERS substrate HOF@Au synergistically CHA-mediated double-end DNA walker as high-efficient signal amplification strategy to achieve ultra-sensitive detection of roxithromycin

Roxithromycin (ROX) is an effective antibiotic, but its prolonged administration may lead to hepatotoxicity and other side effects. To address this concern, the present study introduced a novel strategy that integrated a CHA-mediated dual-end DNA walker with hydrogen-bonded organic frameworks (HOFs) combined with Au nanoparticles (NPs) as efficient SERS substrates, enabling highly sensitive detection of ROX in food. Notably, HOF possessed a large specific surface area and strong adsorption properties that making it excellent platforms for the in-situ synthesis of abundant Au NPs and contributed to robust and uniform SERS signals. When ROX was present, it can trigger the activation of CHA and resulting the formation of a dual-end DNAzyme structure. Meanwhile, under the catalytic action of Mg 2+ , DNAzyme initiated the DNA walker mechanism and generated a substantial amount of Output DNA. Moreover, the Au@4-NTP@Ag core-shell structure generated numerous SERS “hot spots” and combined with the signal-amplifying capability of HOF@Au, leading to a remarkable improvement in SERS sensitivity. Based on this mechanism, the developed sensor employs a “signal-on” strategy for ultra-sensitive detection of ROX, achieving a detection range from 1.0 × 10 −6 to 1.0 × 10 −13  mol/L with a detection limit of 3.72 × 10 −14  mol/L. Furthermore, the method had been successfully applied to the detection of ROX in real food samples, including milk and honey, offering a promising and innovative framework for the development of next-generation SERS biosensors. This approach demonstrated significant potential for highly selective and sensitive antibiotic monitoring in food safety applications.