Single nanoparticle sensing (SNS) is an emerging research field which utilizes single nanoparticles as individual nano-sensors to acquire the qualitative and quantitative information of the analytes in a localized and microscopic sample environment . Both the molecular recognition and signal transduction take place at the surface of a single nanoparticle. Versatile kinds of optical microscopy, such as dark-field microscopy and fluorescence microscopy, are often applied to locating the nano-sensor, and to accessing and analyzing the optical signal it reports. Compared to traditional sensing mechanisms that rely on ensemble nanomaterials, SNS has demonstrated its excellent sensitivity down to single molecule detection by focusing in extremely small volumes in the range of aL~pL. Simultaneous monitoring on many individual nano-sensors in a nano-array further allows for high-throughput and mul tiplex analysis . More importantly, single nanoparticles can be easily int roduced to microscopic and dynamic systems such as living cells to probe specific analytes wi th high temporal and spatial resolution while main taining the excellent sensitivity. In this review, we begin with a brief in troduction on the history and development of SNS, which is fol lowed by its major features. We subsequently survey the recent progresses in this field in the past five years, focusing on the different sens ing principles , single nanoparticle counting and single nanoparticle tracking. We finally provide our perspectives that further developments on nano-probes, optical imaging techniques and data analysis are critical to the growth and applications of SNS in broad fields.

中文翻译：

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基于光学显微镜的单纳米粒子传感

单纳米粒子传感 (SNS) 是一个新兴的研究领域，它利用单个纳米粒子作为单独的纳米传感器来获取局部和微观样品环境中分析物的定性和定量信息。分子识别和信号转导都发生在单个纳米颗粒的表面。多种光学显微镜，如暗场显微镜和荧光显微镜，通常用于定位纳米传感器，并访问和分析它报告的光信号。与依赖于整体纳米材料的传统传感机制相比，SNS 通过聚焦在 aL~pL 范围内的极小体积，展示了其对单分子检测的出色灵敏度。同时监测纳米阵列中的许多单个纳米传感器进一步允许高通量和多重分析。更重要的是，单个纳米粒子可以很容易地引入微观和动态系统，例如活细胞，以高时空分辨率探测特定分析物，同时保持出色的灵敏度。在这篇综述中，我们首先简要介绍了 SNS 的历史和发展，然后是它的主要特点。我们随后调查了过去五年该领域的最新进展，重点关注不同的传感原理、单纳米粒子计数和单纳米粒子跟踪。我们最终提供了我们的观点，即纳米探针的进一步发展，