Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 511143, China.
Department of Neurology and Stroke Center, The first Affiliated Hospital, & Clinical Neuroscience Institute, Jinan University, Guangzhou, 510630, China.
Adv Mater. 2023 Aug;35(33):e2304116. doi: 10.1002/adma.202304116. Epub 2023 Jul 8.
Optical fibers can be effective biosensors when employed in early-stage diagnostic point-of-care devices as they can avoid interference from molecules with similar redox potentials. Nevertheless, their sensitivity needs to be improved for real-world applications, especially for small-molecule detection. This work demonstrates an optical microfiber biosensor for dopamine (DA) detection based on the DA-binding-induced aptamer conformational transitions that occur at plasmonic coupling sites on a double-amplified nanointerface. The sensor exhibits ultrahigh sensitivity when detecting DA molecules at the single-molecule level; additionally, this work provides an approach for overcoming optical device sensitivity limits, further extending optical fiber single-molecule detection to a small molecule range (e.g., DA and metal ions). The selective energy enhancement and signal amplification at the binding sites effectively avoid nonspecific amplification of the whole fiber surface which may lead to false-positive results. The sensor can detect single-molecule DA signals in body-fluids. It can detect the released extracellular DA levels and monitor the DA oxidation process. An appropriate aptamer replacement allows the sensor to be used for the detection of other target small molecules and ions at the single-molecule level. This technology offers alternative opportunities for developing noninvasive early-stage diagnostic point-of-care devices and flexible single-molecule detection techniques in theoretical research.
光纤在早期诊断即时检测设备中作为生物传感器非常有效，因为它们可以避免与具有相似氧化还原电位的分子发生干扰。然而，为了实际应用，特别是对于小分子检测，其灵敏度需要提高。本工作展示了一种基于等离子体耦合位点上的双放大纳米界面上发生的 DA 结合诱导适体构象转变的光学微光纤生物传感器，用于检测多巴胺 (DA)。该传感器在单分子水平上检测 DA 分子时表现出超高灵敏度；此外，本工作提供了一种克服光学器件灵敏度限制的方法，将光纤单分子检测进一步扩展到小分子范围（例如，DA 和金属离子）。结合部位的选择性能量增强和信号放大有效地避免了整个光纤表面的非特异性放大，这可能导致假阳性结果。该传感器可以检测体液中单分子 DA 信号。它可以检测释放的细胞外 DA 水平并监测 DA 氧化过程。适当的适体替换允许传感器用于在单分子水平上检测其他目标小分子和离子。这项技术为开发非侵入性早期诊断即时检测设备和理论研究中的灵活单分子检测技术提供了替代机会。
