Nguyen Minh-Chau, Berto Pascal, Valentino Fabrice, Lemineur Jean-François, Noel Jean-Marc, Kanoufi Frédéric, Tessier Gilles
Université Paris Cité, ITODYS, CNRS, F-75013 Paris, France.
Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
ACS Nano. 2022 Sep 27;16(9):14422-14431. doi: 10.1021/acsnano.2c04792. Epub 2022 Sep 13.
Monitoring chemical reactions in solutions at the scale of individual entities is challenging: single-particle detection requires small confocal volumes, which are hardly compatible with Brownian motion, particularly when long integration times are necessary. Here, we propose a real-time (10 Hz) holography-based nm-precision 3D tracking of single moving nanoparticles. Using this localization, the confocal collection volume is dynamically adjusted to follow the moving nanoparticle and allow continuous spectroscopic monitoring. This concept is applied to study galvanic exchange in freely moving colloidal silver nanoparticles with gold ions generated . While the Brownian trajectory reveals particle size, spectral shifts dynamically reveal composition changes and transformation kinetics at the single-object level, pointing at different transformation kinetics for free and tethered particles.
单粒子检测需要小的共聚焦体积，这与布朗运动很难兼容，特别是在需要长积分时间时。在此，我们提出一种基于实时（10赫兹）全息术的纳米精度单移动纳米粒子三维跟踪方法。利用这种定位，共聚焦收集体积可动态调整以跟踪移动的纳米粒子，并允许进行连续光谱监测。这一概念被应用于研究自由移动的胶体银纳米粒子与生成的金离子之间的电化交换。虽然布朗轨迹揭示了粒子大小，但光谱位移在单物体水平上动态揭示了组成变化和转化动力学，表明自由粒子和束缚粒子具有不同的转化动力学。
