Adrenaline (AD) is an important hormone in central nervous system of mammals, and also works as a medium to transmit signal. The abnormal level of AD in nerve tissues and biological fluids can cause a variety of diseases. In this work, we developed a simple and sensitive dark-field microscopy (DFM)-based single-particle detection (SPD) method for quantitative detection of AD in aqueous solution. MnO₂ layer of GNP@MnO₂ core-shell nanoparticles could be readily etched due to the reducibility of AD. Since the localized surface plasmon resonance (LSPR) of GNPs was sensitive to the dielectric change of local environment, the etching process resulted in an evident color change of the probe and could be easily observed in real time under dark-field microscope. The AD was thus sensitively detected in a wide linear concentration range (0.02–5 μmol/L) with a limit of detection (LOD) of 7.17 nmol/L. Moreover, this method was used for the analysis of AD content in commercial injection and satisfactory recoveries were acquired. As a consequence, the sensing assay demonstrated herein based on GNP@MnO₂ NPs showed great application prospects in molecular recognition and drug quality assay.

肾上腺素（AD）是哺乳动物中枢神经系统的重要激素，也是传递信号的媒介。神经组织和生物体液中AD的异常水平可引起多种疾病。在这项工作中，我们开发了一种简单而灵敏的基于暗场显微镜 (DFM) 的单粒子检测 (SPD) 方法，用于水溶液中 AD 的定量检测。GNP@MnO _{2 的}MnO ₂层由于 AD 的可还原性，核壳纳米粒子很容易被蚀刻。由于 GNPs 的局域表面等离子体共振 (LSPR) 对局部环境的介电变化很敏感，蚀刻过程导致探针颜色发生明显变化，并且可以在暗场显微镜下轻松实时观察。因此，在宽线性浓度范围 (0.02–5 μmol/L) 内可以灵敏地检测到 AD，检测限 (LOD) 为 7.17 nmol/L。此外，该方法用于分析商业注射液中的 AD 含量，获得了满意的回收率。因此，本文展示的基于 GNP@MnO ₂ NPs的传感分析在分子识别和药物质量分析中显示出巨大的应用前景。