The use of multiphase flows in microfluidics to carry dispersed phase material (droplets, particles, bubbles, or fibers) has many applications. In this review paper, we focus on such flows on centrifugal microfluidic platforms and present different methods of dispersed phase material generation. These methods are classified into three specific categories, i.e., step emulsification, crossflow, and dispenser nozzle. Previous works on these topics are discussed and related parameters and specifications, including the size, material, production rate, and rotational speed are explicitly mentioned. In addition, the associated theories and important dimensionless numbers are presented. Finally, we discuss the commercialization of these devices and show a comparison to unveil the pros and cons of the different methods so that researchers can select the centrifugal droplet/particle generation method which better suits their needs.

In this paper, a 3D model of magnetohydrodynamic (MHD) micropump with a rectangular channel was modeled and numerically simulated based on the finite volume method. Effects of geometrical parameters such as depth, width, and length of the side electrodes were studied on the maximum flow rate, maximum pressure, and energy rate of the rectangular MHD channels in constant electric current and constant power supply modes. The multiple attributes decision-making method was used in order to identify the most effective geometrical parameters on the performance of the micropump. Wider channels with long electrodes are identified to be in favor of high performance for high flow rate, high pressure, and energy-efficient demands. A case study of new profile with a widened channel in the pumping section was proposed, and its new geometrical parameters are introduced. Studies at constant energy rate of 1 mW showed that the extension of the channel width (electrode walls) can increase the flow rate up to 1.23 μl/min (34% increase in comparison with non-extended channel). Additionally, it was found that when the extension parameter is set to 3.5 (D/w = 3.5), the flow rate is independent of the elongation parameter (r/R).

The fluidic barrier in centrifugal microfluidic platforms is a newly introduced concept for making multiple emulsions and microparticles. In this study, we focused on particle generation application to better characterize this method. Because the phenomenon is too fast to be captured experimentally, we employ theoretical models to show how liquid polymeric droplets pass a fluidic barrier before crosslinking. We explain how secondary flows evolve and mix the fluids within the droplets. From an experimental point of view, the effect of different parameters, such as the barrier length, source channel width, and rotational speed, on the particles' size and aspect ratio are investigated. It is demonstrated that the barrier length does not affect the particle's ultimate velocity. Unlike conventional air gaps, the barrier length does not significantly affect the aspect ratio of the produced microparticles. Eventually, we broaden this concept to two source fluids and study the importance of source channel geometry, barrier length, and rotational speed in generating two-fluid droplets.

Calcific aortic valve disease (CAVD) is a common cardiovascular disease that affects millions of peopleworldwide. The disease is characterized by the formation of calcium nodules on the aortic valve leaflets,which can lead to stenosis and heart failure if left untreated. The pathogenesis of CAVD is still notwell understood, but involves several signaling pathways, including the transforming growth factorbeta (TGFβ) pathway. In this study, we developed a multiscale computational model for TGFβ-stimulated CAVD. The model framework comprises cellular behavior dynamics, subcellular signalingpathways, and tissue-level diffusion fields of pertinent chemical species, where information is sharedamong different scales. Processes such as endothelial to mesenchymal transition (EndMT), fibrosis, andcalcification are incorporated. The results indicate that the majority of myofibroblasts and osteoblastlikecells ultimately die due to lack of nutrients as they become trapped in areas with higher levels offibrosis or calcification, and they subsequently act as sources for calcium nodules, which contributeto a polydispersed nodule size distribution. Additionally, fibrosis and calcification processes occurmore frequently in regions closer to the endothelial layer where the cell activity is higher. Our resultsprovide insights into the mechanisms of CAVD and TGFβ signaling and could aid in the developmentof novel therapeutic approaches for CAVD and other related diseases such as cancer. More broadly,this type of modeling framework can pave the way for unraveling the complexity of biological systemsby incorporating several signaling pathways in subcellular models to simulate tissue remodeling indiseases involving cellular mechanobiology.