Fiber optic surface plasmon resonance (FO-SPR)-based biosensors have emerged as powerful tools for biomarker detection due to their ability for real-time analysis of biomolecular interactions, cost-effectiveness, and user-friendliness. However, as (FO-)SPR signals are determined by the mass of the target molecules, the detection of low-molecular-weight targets remains challenging and currently requires tedious labeling and preparation steps. Therefore, in this work, we established a new concept for low-molecular-weight target detection by implementing duplexed aptamers on an FO-SPR sensor. In this manner, we enabled one-step competitive detection and could achieve significant signals, independent of the weight of the target molecules, without requiring labeling or preprocessing steps. This was demonstrated for the detection of a small molecule (ATP), protein (thrombin), and ssDNA target, thereby reaching detection limits of 72 μM, 36 nM, and 30 nM respectively and proving the generalizability of the proposed bioassay. Furthermore, target detection was successfully achieved in 10-fold diluted plasma, which demonstrated the applicability of the assay in biologically relevant matrices. Altogether, the developed one-step competitive FO-SPR bioassay opens up possibilities for the detection of low-molecular-weight targets in a fast and straightforward manner.

中文翻译：

---

由 DNA 纳米技术实现的多功能一步竞争性光纤表面等离子体共振生物测定

基于光纤表面等离子体共振 (FO-SPR) 的生物传感器由于能够实时分析生物分子相互作用、成本效益和用户友好性，已成为生物标志物检测的强大工具。然而，由于 (FO-)SPR 信号由目标分子的质量决定，低分子量目标的检测仍然具有挑战性，目前需要繁琐的标记和制备步骤。因此，在这项工作中，我们通过在 FO-SPR 传感器上实施双工适配体，建立了低分子量目标检测的新概念。通过这种方式，我们启用了一步竞争性检测，并且可以获得显着的信号，与目标分子的重量无关，无需标记或预处理步骤。这已被证明可用于检测小分子 (ATP)、蛋白质（凝血酶）和 ssDNA 靶标，从而分别达到 72 μM、36 nM 和 30 nM 的检测限，并证明了所提议的生物测定的普遍性。此外，在 10 倍稀释的血浆中成功实现了目标检测，这证明了该测定在生物相关基质中的适用性。总之，开发的一步竞争 FO-SPR 生物测定为以快速和直接的方式检测低分子量目标开辟了可能性。这证明了该测定在生物相关基质中的适用性。总之，开发的一步竞争 FO-SPR 生物测定为以快速和直接的方式检测低分子量目标开辟了可能性。这证明了该测定在生物相关基质中的适用性。总之，开发的一步竞争 FO-SPR 生物测定为以快速和直接的方式检测低分子量目标开辟了可能性。