Study on ultra-precision viscosity measurement using a fluorescent probe

在这项研究中，我们提出了一种新的方法来评估小样品的粘度，基于旋转扩散系数的纳米探针使用荧光偏振法。在使用寿命小于10 ns的荧光探针(即荧光素，荧光寿命4.3 ns，直径1.1 nm)的情况下，可以将用于粘度测量的荧光偏振分析速度加快到100 MHz。此外，通过使用直径为1 nm的探头，由于减小了探头惯性力的影响，提高了布朗运动扩散模型测量粘度的精度，从而构建了小样本旋转扩散系数计算的基本系统。验证了本文提出的基于旋转扩散系数的小样本粘度估算方法的可行性。

In this study, we suggest a novel method for evaluating the viscosity of small samples based on the rotational diffusion coefficient of the nano probe by using fluorescence polarization method. In the case of using the fluorescence probe with lifetime less than 10 ns ( i.e. Fluorescein, fluorescence lifetime 4.3ns, diameter 1.1nm) , it is possible to accelerate the rate of fluorescence polarization analysis for viscosity measurement to 100MHz. Furthermore, by using the probe with diameter of 1nm, the measurement accuracy of the viscosity using a diffusion model of the Brownian motion is improved due to minimizing the influence of the inertial force of probe.As a result, we construct the fundamental system to evaluate the rotational diffusion coefficient for small sample. We verify the feasibility of proposed method for evaluating the viscosity of small sample based on the rotational diffusion coefficient.