Effect of geometrical shapes on 3D hydrodynamic focusing of a microfluidic flow cytometer

This paper focuses on the effect of geometrical cross section between rectangular and circular shapes on the hydrodynamic focusing of a micro flow cytometer device. The effect of fluid flow ratio between the main and sheath channels on the focusing width is studied. This study has been performed using a COMSOL Multiphysics simulation tool. The results showed that focusing width decreases as the ratio between main channel and sheath channels are increased. The concentration at long-range is studied and indicated that circular shape can sustain a higher concentration at the centre along the channel compared with rectangular shape. The velocity at the cross-section of the channel-junction shows that circular shape produces higher velocity at the centre of the channel compare to that of the rectangular shape. The effect of flow ratio and geometrical shape are significantly vital for microfluidic system which utilizes hydrodynamic focusing for biological and chemical analysis. From the result, micro flow cytometer studied able to use for human body cells such as glucose, virus, red blood cells and white blood cells which have a range size of 2-120 microns.