Yi He,Xiaoyu Yang,Shunbi Xie,Runzi Zhang,Yao Liu,Mengjun Wang
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.
Runzi Zhang,Shunbi Xie,Xiaoyu Yang,Wanyi Xiong,Yi He
Currently, surface-enhanced Raman scattering (SERS) biosensors face practical challenges, including SERS substrate waste and unsatisfactory detection results. Accordingly, the highly efficient and regenerable SERS substrate HOF@Au was collaborated with a target-triggered identifying-cleaving-rolling-assembly cycling nanodevice (ICRACN) as a cascade signal amplification system to achieve an ultrasensitive detection of roxithromycin (RXM). In this system, abundant Au nanoparticles (NPs) were reduced in situ on the surface of alkali-resistant HOF-102 to form a uniform and high-enhancement SERS substrate HOF@Au, thereby enhancing the accuracy and stability of the sensor. Furthermore, aptamer-mediated specific recognition, efficient cleavage activity of DNA nanorollers, and a pH-responsive DNA triplex structure were engineered to construct ICRACN. In the presence of the target, it was specifically recognized by the aptamer, leading to the activation of the DNAzyme. Meanwhile, the dynamic nanorollers were triggered to initiate cleavage of a specific site along a defined pathway, enabling highly efficient signal amplification. Concurrently, the triplex structure formed by the two single-stranded DNA atoms on the SERS substrate was opened, allowing the capture of the SERS tag and generating a pronounced SERS signal. The proposed strategy achieved the sensitive detection of RXM with a low limit of detection of 3.97 × 10–14 mol/L. Moreover, modulation of pH induced reversible folding and unfolding of the triplex structure to facilitate regeneration of the SERS substrate, which simplified operational procedures and reduced detection costs. As a result, this work presents a novel, regenerable SERS biosensor and offers valuable insights into the design of multifunctional sensing platforms for analytical applications.
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