An approach of flow velocity measurement on microfluidic chip by near-field scanning microwave microscopy

Abstract

A novel approach for flow velocity measurements on a microfluidic chip using near-field scanning microwave microscopy (NSMM) is proposed. It does not require the tested sample to contain visible particles, as the intrinsic electromagnetic properties of the fluid can be detected. Compared with conventional flowmetry, NSMM can measure flow velocity of the tested specimen without any invasive detectors inside or in contact with the specimen, and it can preserve original characteristics of the sample. The flow velocity of different types of solutions is obtained in point scanning, and flow velocity distribution in a microfluidic channel is illustrated in line scanning of NSMM measurement. The flow velocity distribution in microfluidic channel demonstrates distinctive differences between flow velocities of adjacent points, and the microfluidic channel is recognized with a lateral resolution of 10 μm. This approach can help optimize localized flow velocity measurement in drug screening and chemical reaction, and it can be developed for 2D/3D flow velocity imaging in chemical industry and biomedical field.