Two-dimensional fluid viscosity measurement in microchannel flow using fluorescence polarization imaging

Abstract

This study describes the development of a noncontact and two-dimensional fluid viscosity measurement technique based on fluorescence polarization microscopy. This technique exploits fluorescence depolarization due to rotational Brownian motion of fluorophores and determines fluid viscosity in microchannel flow by measuring steady-state fluorescence polarization. The main advantage of the technique is that planar distributions of fluid viscosity can be visualized by noncontact optical measurement, while commonly-used mechanical viscometers measure the viscosity of bulk liquids. Moreover, steady-state polarization measurements are realized using a simpler experimental setup compared to other noncontact techniques such as time-resolved fluorescence lifetime/polarization measurements. The relationship between the fluid viscosity (µ) and the fluorescence polarization degree (P) was experimentally obtained using casein molecules labeled with fluorescein isothiocyanate as a fluorescent probe. The fluid viscosity was controlled within the range of 0.7-3.0 mPa s, which is the range often encountered in biological materials, by mixing sucrose or glucose with the solution. The fluid temperature was maintained uniform at 30 • C during the measurement. The calibration result showed that 1/P linearly increased with 1/µ which qualitatively agreed well with the theoretical prediction. The measurement uncertainty was 7.5%-9.5% based on the slope of the calibration curve. The viscosity gradient generated by the mass diffusion between the two solutions co-flowing in the Y-shaped microchannel was clearly visualized under uniform temperature conditions by applying the calibration curve. Finally, the influence of the temperature change on P was experimentally evaluated. The results supported the applicability of the present technique for visualization of the viscosity distribution induced by temperature change. These results confirmed the feasibility of the present technique for analyzing microscale viscosity fields associated with mass transport or temperature change.

Principle and Implementation of Stokes Vector Polarization Imaging Technology

“…2022, 12, x FOR PEER REVIEW 2 of 13 polarization imaging is a new kind of photoelectric detection system, the method of using polarization imaging measurement objective reflection of the degree of polarization and polarization angle information, can effectively make up for the inadequacy of traditional imaging, solve traditional photometry is difficult to solve the problem in target recognition, and obtain the result of the high precision, and on the basis of traditional strength imaging increased the polarization information dimension, The polarization information of each point in the image can be obtained as well as the distribution of light intensity in two-dimensional space. At present, polarization imaging technology has shown potential application prospects in biomedicine [1,2], modern military [3,4], industrial detection [5][6][7], descattering imaging [8][9][10][11], navigation [12] and other fields. Polarization imaging methods mainly include Stokes vector imaging and Muller matrix imaging, and Stokes vector can be expressed as 4 × 1 column matrix or 1 × 4 row matrix, which is more convenient in describing fully polarized light, natural light and partially polarized light.…”

Measurement Modeling and Performance Analysis of a Bionic Polarimetric Imaging Navigation Sensor Using Rayleigh Scattering to Generate Scattered Sunlight

“…The proposed analysis method is generalized for all BPINSs. (2) The key error factors affecting the measurement accuracy of BPINS are quantitatively investigated using a skylight with a known polarization state generated by Rayleigh scattering as the incident light source, which is similar to the polarization pattern of an outdoor Rayleigh clear sky. (3) This work can guide the calibration of BPINS and provide a theoretical basis for the optimal design of BPINS.…”

“…Polarization is another dimension of light, just like spectrum and intensity, which can provide distinct and useful information about a visual scene [ 1 ] and is applied in many scenarios, such as microscopy imaging [ 2 ], optical precision measurement [ 3 , 4 ], and biological polarization navigation [ 5 , 6 , 7 ]. Many animals, particularly insects, are sensitive to the polarization of light and use this information for navigation, detection, and communication [ 8 ].…”

Hyperspectral Channel-Modulated Static Birefringent Fourier Transform Imaging Spectropolarimeter with Zoomable Spectral Resolution

“…An imaging polarimeter captures the two-dimensional spatial polarization information of the target, which is widely used in biomedicine [28,29], industrial detection [30][31][32], de-scattering imaging [33][34][35][36], and other fields due to its ability in describing the roughness and contour of targets. The channel-modulated imaging spectropolarimeter (CMIS) [37][38][39] developed on the basis of FTIS can simultaneously obtain the spectra and full polarization information of the target, which has attracted significant attention for its compact structure and high stability.…”