Velocity measurements of physiological flows in microchannels using a confocal micro-PIV system

• Main Author: Lima, Rui A.
• Publication Date: 2005
• Other Authors: Wada, Shigeo, Tsubota, Ken-ichi, Yamaguchi, Takami
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/10198/2016
• topic: Red blood cell; Confocal micro-PIV; Microchannel; Microcirculation

The detail measurements of velocity profiles of in vitro blood flow in micorchannels are fundamental for a better understanding on the biomechanics of the microcirculation. Despite the high amount of research in microcirculation, there is not yet any detailed experimental information about flow velocity profiles, RBCs deformability and aggregation in microvessels (diameter in the order of 100μm or less). These lack of knowledge is mainly due to the absence of adequate techniques to measure and quantitatively evaluate fluid mechanical effects at a microscopic level [1, 2]. During the years the most research work in this area has focused in experimental studies using techniques such as laser Doppler anemometry (LDA) or conventional particle image velocimetry (PIV). However, due to limitations of those techniques to study effects at a micro-scale level, Meinhart and his colleagues [3] have proposed a measurement technique that combines the PIV system with an inverted epi-fluorescent microscope, which increases the resolution of the conventional PIV systems [3]. More recently, considerable progress in the development of confocal microscopy and consequent advantages of this microscope over the conventional microscopes [4, 5] have led to a new technique known as confocal micro-PIV. This technique combines the conventional PIV system with a spinning disk confocal microscope (SDCM). Due to its outstanding spatial filtering technique together with the multiple point light illumination system, this kind of microscope has the ability to obtain in-focus images with optical thickness less than 1 μm, task extremely difficult to be achieved by using a conventional microscope. As a result, by combining SDCM with the conventional PIV system it is possible to achieve a PIV system with not only extremely high spatial resolution but also with capability to generate 3D velocity profiles. The main purpose of the present study is to evaluate the performance of our confocal micro-PIV system in order to investigate its ability to study the behaviour of non-homogenous fluids such as physiological fluids.