Micromixing has a practical application in analyzing of many biochemical and biologicals detection devices of LAB-on-a-CHIP (LOC). The conventional static micromixers require the channel with more lengths and also require times to reach to complete mixing owing to its dependence on transverse diffusion. However, in the electrokinetic micromixers, as the surface properties of the microchannel run the electro-osmotic flow characteristics, surface heterogeneity (non-uniform zeta potentials) can be seen to make vortices or specific flow structures for better mixing performance. This study aims to use computational fluid dynamics (CFD) to numerically compare the concentration rate of the various electrokinetic micromixers in in the presence of the electric conductor. The results revealed that the off-center microchannel design in a micromixer can augment the rate of concentration. In addition, circular microchannel design showed better mixing compared to the triangular and square designs. These results are useful not only for understanding of the profiles of concentration in the electrokinetic micromixers, but also for providing a comprehensive information on the design of the microchannels, which may result in better mixture in the fluids

Recent advances in science and technology caused the Revolution in many different fields of science and Industry. The term LAB on CHIP or performing difficult analyses only in a short time and in a small space is an expression which becomes very common in recent years. Today, the things which were wishes in the past, are becoming real and inserted in the real life of humankind. In this article, it is tried to study and discuss a special kind of LAB on CHIP technology, which is called microfluidic (or microchannel). Although this is a vast technology, and it was inserted in many branches of Science and Industry, but here, we have discussed only the applications of this technology in medical and biological diagnostic fields. In this article, we have especially surveyed the devices which were made based on this technology for DNA analysis, devices for detection based on separation, devices for cell sorting and handling and devices for protein-based applications.

Introduction: The microfluidic device is highly optimized to remove oocytes from the cumulus-corona cell mass surrounding them. Additionally, it effectively captures and immobilizes the oocytes, aiding in assessing their quality and facilitating the injection of sperm into the oocyte. In this study, a novel microfluidic CHIP was designed and manufactured using conventional soft lithography methods. Methods: This research proposes the utilization of a microfluidic CHIP as a substitute for the conventional manual procedures involved in oocyte denudation, trapping, and immobilization. The microfluidic CHIP was modeled and simulated using COMSOL Multiphysics® 5. 2 software to optimize and enhance its design and performance. The microfluidic CHIP was fabricated using conventional injection molding techniques on a polydimethylsiloxane substrate by employing soft lithography methods. Results: A hydrostatic force was applied to guide the oocyte through predetermined pathways to eliminate the cumulus cells surrounding the oocyte. The oocyte was subsequently confined within the designated trap region by utilizing hydraulic resistance along the paths and immobilized by applying vacuum force. Conclusion: The application of this CHIP necessitates a lower level of operator expertise compared to enzymatic and mechanical techniques. Moreover, it is feasible to continuously monitor the oocyte's state throughout the procedure. There is a reduced need for cultural media compared to more standard approaches.

Intracytoplasmic sperm injection (ICSI) is one of the most successful techniques of Assisted Reproductive Technology (ART) and is mostly in use for the treatment of infertility with male factors. In this method, before injecting sperm into the intracytoplasmic of the oocyte, cumulus cells around the oocyte must be stripped to facilitate the injection process. To achieve this, both enzymatic and mechanical methods are used in embryological LABoratories for denudation, which has major deficiencies, including the possibility of damaging the oocyte prior to the injection process. In this research, a microfluidic-based device is introduced for the separation of cumulus cells around the oocyte with minimum manual operations. The results prove high efficiency, and non-destructive denudation of the oocyte with the reduced amount of culture medium leads to the low-cost preparation process of oocytes. The process can also be integrated with ICSI CHIPs under development and will be reported shortly.

Early diagnosis of hypertensive diseases such as cancer plays an essential role in preventing disease progression. The main cause of death from cancer is the reappearance of the disease due to the release of tumor cells in the blood of the patient. Among the various methods that have been devised for monitoring blood in recent years, the techniques based on micro-scale flow have specially been considered. The development of these methods has led to the emergence of microfluidics LABoratories on the CHIPs, which their main advantages are low prices and simplicity. Since the particles’ sizes are different in the flow of blood, the direction of these particles in the micro-channels will vary due to the different forces, and therefore they can be analyzed to the design of bio-microCHIPs. In the present study, a two-phase flow containing spherical particles with the dimensions of blood cells was considered, and the forces affecting the particles of this current, including the lift forces and drag forces, were studied using COMSOL software. For this purpose, a micro divergent channel was designed and the effect of ratio of the outlet width to the inlet width (Aspect Ratio) as an effective geometric parameter in the biological particle separation was analyzed. The study of the effect of particle dimensions and various geometric parameters of the channel on bio-particles separation are the main goals of this research. The results show that by increasing the Aspect ratio, focusing of the larger particles would increase at the outlet of micro-channel.

This paper focuses on minimizing the C4D sensor for the LAB-on-a-CHIP (LOC) and how the parameters such as the CHIP manufacturing materials, ion charge, frequency, and the geometry of the electrodes affect it through COMSOL software. The simulation results show if the CHIP is made of glass, then the current density increases to 0. 003 A/m2 at the time of ion presence. Also, the current density reaches 0. 0015 A/m2 when the CHIP is made of poly dimethyl siloxane (PDMS). By using a combination of these two materials, in addition to achieving the benefits of PMDS, the sensitivity of the sensor also increases. Moreover, the entrance frequency enhancement prevents any sudden flow density change. By changing the ionic charge from 1 to 5, conductivity changes from 1×10-7 to 8×10-7 Siemens/m. The design of the CHIP with four electrodes also increases the sensitivity of the sensor due to the strong current density in the solution body. Choosing the appropriate C4D sensor on a high-sensitivity CHIP can in the future provide many advancements in medical and medical diagnostics.