Wang Yi, Jing Wenwen, Tao Nongjian, Wang Hui
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
Department of Medical Microbiology and Parasitology, Shanghai Medical College of Fudan University, Shanghai 200032, China.
ACS Sens. 2021 Feb 26;6(2):523-529. doi: 10.1021/acssensors.0c02184. Epub 2020 Dec 7.
Measuring binding processes at the single-molecule level underpin significant functions in understanding biological events. Single-nanoparticle imaging techniques are providing a new concept for mapping the heterogeneous behaviors and characterizations of individual dynamics such as molecule-molecule interactions. Here, we develop the optical imaging techniques for directly counting and monitoring the binding and motion events of single nanoparticles linked to the substrate via the specific and reversible interactions between biomolecules. The one-step digital immunoassay realizes the biomolecular detection based on dynamic counting of the single nanoparticle binding event to substrate with the bright-field imaging. The detection limit achieves 8.4 pg/mL for procalcitonin with detection time of 14 min. Meanwhile, we map the accurate trajectory of single nanoparticle switching between different target molecules among the plane with the total internal reflection imaging technique, which reveals the spatial coordinates of single target molecules on the substrate surface with high spatial and temporal resolutions.
在单分子水平上测量结合过程是理解生物事件中重要功能的基础。单纳米颗粒成像技术为描绘诸如分子间相互作用等个体动力学的异质性行为和特征提供了一个新概念。在此，我们开发了光学成像技术，用于通过生物分子之间的特异性和可逆相互作用直接计数和监测与底物相连的单个纳米颗粒的结合和运动事件。一步式数字免疫测定通过明场成像基于对单个纳米颗粒与底物结合事件的动态计数实现生物分子检测。降钙素原的检测限达到8.4 pg/mL，检测时间为14分钟。同时，我们利用全内反射成像技术绘制了单个纳米颗粒在平面内不同目标分子之间切换的精确轨迹，以高空间和时间分辨率揭示了底物表面单个目标分子的空间坐标。
