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![5.5 (a) Balance of shear gradient lift force and wall lift force results in the inertial equilibrium positions in a Poiseuille flow. (b) The net lift coefficient is a function of particle lateral position x and Reynolds number Re. Reproduced from reference [67]](profile/Jun-Zhang-69/publication/309275274/figure/fig9/AS:418899628707850@1476884862900/55-a-Balance-of-shear-gradient-lift-force-and-wall-lift-force-results-in-the-inertial.png)
5.5 (a) Balance of shear gradient lift force and wall lift force results in the inertial equilibrium positions in a Poiseuille flow. (b) The net lift coefficient is a function of particle lateral position x and Reynolds number Re. Reproduced from reference [67]
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In microfluidics, the typical sample volume is in the order of nL, which is incompatible with the common biosample volume in biochemistry and clinical diagnostics (usually ranging from 1 μL to approximately 1 mL). The recently emerged inertial microfluidic technology offers the possibility to process large volume (∼mL) of biosample by well-defined...
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Quantitative detection of RNA is important in molecular biology and clinical diagnostics. Nucleic acid sequence-based amplification (NASBA), a single-step method to amplify single-stranded RNA, is attractive for use in point-of-care (POC) diagnostics because it is an isothermal technique that is as sensitive as RT-PCR with a shorter reaction time. H...
Citations
... 32 These are a consequence of the different viscosities of the phases, the dimensions of both the microchannel and the phase flow section, and the flow velocity in each of the phases. 33 GFP-LYTAG has been previously described as having an increased partition to the polymer rich phase (PRP), due to salting out effects that decrease the solubility of the protein in the salt rich phase (SRP), combined with the increased affinity for PEG molecules given by LYTAG ligand. 25 The partition of E. coli in an ATPS has been described as being dependent on the surface hydrophobicity and net charge of the cell, and on the ionic strength of the system, 25,34 with its behaviour also being influenced by the flow rate and medium viscosity in microchannels. ...
BACKGROUND
Microfluidic devices have been increasingly used as tools to accelerate the development of new biomanufacturing methods, given their ability to test a large set of variables in a short amount of time with minimal reagent consumption. However, while being able to expedite a bioprocess design, the modular aspect of these devices has not been systematically explored, with most applications focusing on single unitary operations. This paper explores the modular design of these devices through the development of an integrated microfluidic chip.
RESULTS
Two separate unitary operations were included into a single device for continuous operation: product release by chemical cell lysis and product concentration by aqueous two‐phase system. In this way, it is possible to screen multiple conditions for each operation and evaluate their combined effect on the final product, making this a great tool in the development and optimization of a process. A recombinant Escherichia coli (E. coli) strain producing green fluorescent protein (GFP) was used as model system, which allows for lysis efficiency and partition coefficient to be evaluated by fluorescence microscopy. A chemical lysis solutions was used in the lysis step, presenting lysis efficiencies of about 100%, while a polyethylene glycol (PEG)/phosphate system was screened for the separation stage, presenting partition coefficients of about 4.
CONCLUSIONS
The integrated device allowed for the continuous screening of multiple combinations of operation conditions, highlighting, for example, conditions where improvements on the lysis efficiency subsequently impaired the separation, decreasing the partition of the target product, thus demonstrating the need for the evaluation of a process in its entirety. In this way, the microfluidic device delivered a rapid process screening and optimization, with very low reagent consumption, and using a simple fluorescence microscope for data collection. © 2023 Society of Chemical Industry (SCI).
... V t > 0 indicates that the particle moves faster than the corresponding fluid element, leading the flow. Adapted from Zhang et al. (2017). d Saffman force on a sphere in a simple shear flow. ...
... V t < 0 means that the particle moves slower than the fluid ele-ment, lagging the flow. Adapted from Zhang et al. (2017). e Forces on particle when boundary (wall) is present on only one side. ...
... e Forces on particle when boundary (wall) is present on only one side. Adapted from Zhang et al. (2017). f Forces on particle when boundary (wall) is present on both the sides. ...
With continuous efforts of researchers all over the world, the field of inertial microfluidics is constantly growing, to cater
to the requirements of diverse areas like healthcare, biological and chemical analysis, materials synthesis, etc. The scale,
automation, or unique physics of these systems has been expanding their scope of applications. In this review article, we have
provided insights into the fundamental mechanisms of inertial microfluidics, the forces involved, the interactions and effects
of different applied forces on the suspended particles, the underlying physics of these systems, and the description of numerical
studies, which are the prime factors that govern designing of effective and practical devices.. Further, we describe how
various forces lead to the migration and focusing of suspended particles at equilibrium positions in channels with different
cross-sections and also review various factors affecting the same. We also focus on the effect of suspended particles on the
flow of fluids within these systems. Furthermore, we discuss how Dean flows are created in a curved channel and how different
structures affect the creation of secondary flows, and their application to mixing, manipulating, and focusing particles
as fluid. Finally, we describe various applications of microfluidics for diagnostic and other clinical purposes, and discuss the
challenges and advancements in this field. We anticipate that this manuscript will elucidate the basics and quantitative aspects
of inertial fluid dynamic effects for application in biomedicines, materials synthesis, chemical process control, and beyond.
... Although two-way coupling can give more accurate results, as it was assumed that the concentration of magnetic particles is low, the effect of momentum transfer from the particle to the fluid could be ignored (Khashan et al. 2014;Gómez-Pastora et al. 2019). Lastly, the inertial fluidic force was determined to be neglectable as we used flow rates low enough in our simulations such that the Reynolds number of our systems were below 1 (Amini et al. 2014;Zhang et al. 2017). ...
Magnetophoresis is one of the most popular particle manipulation schemes used in microfluidic devices. Predicting the performance of arbitrary magnetophoretic module via simulation is crucial for the realization of high-performance, purpose-built magnetophoretic devices. However, the simulation process may take a long time, slowing down the simulation throughput. This work presents a novel algorithm to rapidly predict the trajectory of magnetic particles in microfluidic devices with arbitrary magnetophoretic structures under continuous fluidic flow conditions. Based on the Eulerian–Lagrangian approach, by employing numerically calculated magnetic force and fluidic velocity datasets obtained by finite element analysis software, we used an exponential integrator inspired numerical method to solve for the motion of magnetic particles in the system with the assumption that the magnetic and fluidic forces are constants within a small period of time. The results showed that, for our application, the order of truncation error of our algorithm is comparable with the 4th Order Runge–Kutta method and commercial Runge–Kutta based solver ODE45 from MATLAB. Furthermore, our algorithm is inherently stable, thus enabling the use of arbitrary time stepping values without the need of adaptive step size adjustment, which significantly reduces simulation time when compared to the 4th Order Runge–Kutta method and ODE45. In our simulations, a maximum of 40 times reduction in simulation time can be achieved. The proposed algorithm and the performed simulations are validated experimentally.
... Inertial microfluidic devices use inertial migration to drive particles traveling through a viscous fluid to an equilibrium position according to their density, size, or shape within a system with geometrical symmetry [59,60]. Inertial migration is induced by the sum of an inertial lift force and a drag force, both generated by secondary flows [61,62] produced by the geometry of the microchannel and Biosensors 2022, 12, 191 4 of 35 the intrinsic properties of the fluid. ...
Lab-on-a-Chip (LoC) devices are described as versatile, fast, accurate, and low-cost platforms for the handling, detection, characterization, and analysis of a wide range of suspended particles in water-based environments. However, for gas-based applications, particularly in atmospheric aerosols science, LoC platforms are rarely developed. This review summarizes emerging LoC devices for the classification, measurement, and identification of airborne particles, especially those known as Particulate Matter (PM), which are linked to increased morbidity and mortality levels from cardiovascular and respiratory diseases. For these devices, their operating principles and performance parameters are introduced and compared while highlighting their advantages and disadvantages. Discussing the current applications will allow us to identify challenges and determine future directions for developing more robust LoC devices to monitor and analyze airborne PM.
... The channel width and height are 200 and 58 μm. Figure 2C demonstrates the results of this preliminary study. It is found that the blood cells distribute quite uniformly at 5 μL/sec (or Re < 1) for Figure 2C (2) Curve Channel for Dean Flow Since the inertial migration could provide a RBCs/WBCs separation efficiency at ~89.8% [36,37] in the straight rectangular channel, a secondary flow by using Dean flow is introduced to further enhance the separation efficiency. A series of curve channels are added to provide Dean flow, which can aid lateral particle/cell migration. ...
A microfluidic chip, which can separate and enrich leukocytes from whole blood, is proposed. The chip has 10 switchback curve channels, which are connected by straight channels. The straight channels are designed to permit the inertial migration effect and to concentrate the blood cells, while the curve channels allow the Dean flow to further classify the blood cells based on the cell sizes. Hydrodynamic suction is also utilized to remove smaller blood cells (e.g., red blood cell (RBC)) in the curve channels for higher separation purity. By employing the inertial migration, Dean flow force, and hydrodynamic suction in a continuous flow system, our chip successfully separates large white blood cells (WBCs) from the whole blood with the processing rates as high as 1 × 108 cells/sec at a high recovery rate at 93.2% and very few RBCs (~0.1%).
... Microfluidics and Nanofluidics are comparatively a new branch of Micro/Nano electromechanical systems (MEMS/NEMS) which has made widespread development in the last two decades [1]. This development has directed to an increasing awareness for the investigation of laminar flow in micro and nanochannels [2,3]. The use of these channels in all biological and biomedical micro and nano scale systems is wide spread [4]. ...
This research work presents the simulation and analysis of blood flow in tortuous veins. Three different sized nano channels like spiral, u-shape and curvilinear have been simulated using ANSYS FLUENT. The radius of 200 nm has been considered for all channels during simulation. Flow rate and velocity of these channels have been determined. For spiral, Ushape and curvilinear channels, the flow rate and velocity of 236 pL/s and 18.73 cm/s, 245 pL/s and 19.45 cm/s and 248.8 pL/s and 19.75 cm/s have been observed respectively.
Microfluidics is a rapidly evolving multidisciplinary field that relies on the manipulation of minute volumes of fluids in submillimeter-sized channels with application in chemistry, biotechnology, and health, among other relevant areas. At this scale, a paradigm shift takes place, as phenomena that are unnoticed at the macroscale emerge, since viscous, capillary, and surface tension effects tend to overcome gravity and inertial effects. Therefore, flow behavior often contradicts our macroscopic intuition, yet may easily become more predictable and thus controllable. This chapter focuses on the physics aspects underlying microfluidics. Thus, the basics of fluid mechanics are introduced and the governing equations for fluid flow are presented. Mass transfer and in particular diffusion and diffusion advection aspect are introduced and discussed and complemented with a brief incursion in the strategies for mixing at the microscale, developed to overcome the limitations of diffusion-based processes. Surface tension and capillarity effects are described and their significance in microfluidics is elucidated, also considering their impact in droplets/bubbles formation and multiphase flow.
Metastasis is responsible for 90% of all cancer-related fatalities. CTCs are difficult to detect due to their rarity. Currently, the devices that aid in the detection of CTCs have limitations, such as a high price, complex apparatus, or low sample purity. Consequently, the purpose of this research is to construct and enhance a microfluidic device with a tapered angle. This device aims to outperform conventional microfluidic devices in terms of cost, sample purity, and apparatus. Using the finite element simulation software COMSOL Multiphysics, two studies are conducted, the first of which examines the effect of taper angle on particle separation and the second of which examines the effect of flow rate on particle separation. This design enables particle separation based on hydrodynamic theory and the sedimentation process. A mixture of 3 μm and 10 μm polystyrene (PS) microbeads were effectively separated when the taper angle approached 20 degrees, and separation continued until the taper angle reached 89 degrees. Using 12° and 6° taper angles, 3 μm, and 10 μm polystyrene microbeads were not effectively separated using finite element simulation. The proposed product is functionally enticing despite the fact that this design utilizes a passive separation technique. This technology provides uncomplicated, label-free, continuous separation of numerous particles in a self-contained device without the need for cumbersome equipment. Consequently, both point-of-care diagnostic instruments and micro total analytic systems could utilize this device.
Microfluidic systems enable manipulating fluids in different functional units which are integrated on a microchip. This chapter describes the basics of microfluidics, where physical effects have a different impact compared to macroscopic systems. Furthermore, an overwiew is given on the microfabrication of these systems. The focus lies on clean-room fabrication methods based on photolithography and soft lithography. Finally, an outlook on advanced maskless micro- and nanofabrication methods is given. Special attention is paid to laser structuring processes.
Inertial microfluidics has attracted significant attention in recent years due to its superior benefits of high throughput, precise control, simplicity, and low cost. Many inertial microfluidic applications have been demonstrated for physiological sample processing, clinical diagnostics, and environmental monitoring and cleanup. In this review, we discuss the fundamental mechanisms and principles of inertial migration and Dean flow, which are the basis of inertial microfluidics, and provide basic scaling laws for designing the inertial microfluidic devices. This will allow end-users with diverse backgrounds to more easily take advantage of the inertial microfluidic technologies in a wide range of applications. A variety of recent applications are also classified according to the structure of the microchannel: straight channels and curved channels. Finally, several future perspectives of employing fluid inertia in microfluidic-based cell sorting are discussed. Inertial microfluidics is still expected to be promising in the near future with more novel designs using various shapes of cross section, sheath flows with different viscosities, or technologies that target micron and submicron bioparticles.
