Method For Separation Of Particles Research Articles

Particle Focusing and Separation in the Low Aspect Ratio Serpentine‐Hook Shape Microarray

ABSTRACTIn recent years, researchers have been heavily focused on developing effective techniques for isolating and counting particles. Particle separation methods are enhancing disease point of care and treatment applications. Separation techniques not only increase the chance of early detection of illness but also greatly improve the success rate of treatment. This article introduces a passive microarray separator with a low aspect ratio (<20%). By incorporating a low aspect ratio design, the flow inertial term is effectively diminished, leading to a creeping flow at the channel. This strategy results in negligible lift force and mixing effect on particles. Terminating the mentioned factors provides a channel with sensitive focusing properties. In the proposed research we enhanced a hook‐shaped geometry to increase regional centrifugal force. This configuration results in size‐base particle separation. An expansion was also added to improve the performance of the channel. To validate the functionality and limitations of the designed channel numerical simulation and experimental tests were conducted. To provide better insights into the low aspect ratio separator a numerical simulation using COMSOL Multiphysics has been established. The experiments indicated 91% purity at an input flow of 720 µL/min.

Micro- and Nano-Pollutants from Tires and Car Brakes Generated in the Winter Season in the Poznan City Urban Environment

This research, focusing on the environmental impact of tire and brake disc pad wear, constitutes a significant area of transport-related studies. These two key vehicle components are not only the most frequently worn but also generate micro- and nano-pollutants (i.e., rubber, metal oxides) that potentially harm the environment. Over half of the globally produced natural and synthetic rubbers, which amounted to about 30 million tons in 2022, are used for tire production. This work focuses on the study of roadside snow, sand, and standing water deposits from various locations in the urban agglomeration (Poznań, Poland) during the winter season, determining their qualitative composition and the quantitative content of pollutants originating from tire abrasion. In addition, the method of washing nano- and micro-rubber particles and their full characteristics was also presented. Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic studies, optical and scanning electron microscopy (SEM-EDS), particle size studies using a dynamic light scattering (DLS) particle analyzer, and thermogravimetric analysis (TGA) were conducted for a detailed characterization of the pollutants in the environment. The conducted particle separation methods allowed for the extraction of a fraction mainly containing gum residues with particle sizes less than 2 µm. The results of these tests make it possible to estimate the level of contamination with rubber and metal residues during the abrasion of tires, pads, and brake discs while driving, which is crucial for understanding the impact of vehicle part exploitation on the environment.

Research on particle separation microfluidic chip based on standing surface acoustic wave

Microparticle and cell separation is a key process in the study of cell properties, clinical diagnosis and disease treatment. In this paper, a particle separation method based on the combination of surface acoustic wave and microfluidic technology is proposed, which uses standing surface acoustic wave to achieve the separating of polystyrene microparticles of different sizes twice in a continuous flow. Through numerical simulation of the device model and particle trajectory simulation, the optimum particle separation parameters were determined. The particle separation microfluidic chip has successfully realized the particle separation. The separation yield of 5 μm particles is about 92.1%. The separation rate of 1 μm particles is about 83.3%.

Preparability of Iron Ore from Yakovlevo Deposit, Kursk Magnetic Anomaly, Using Coarse Particle Separation Methods

Preparability of Iron Ore from Yakovlevo Deposit, Kursk Magnetic Anomaly, Using Coarse Particle Separation Methods

Frequencies of Diagnostically Significant Polymorphisms of Hereditary Breast Cancer Forms in BRCA1 and BRCA2 Genes in the Kazakh Population.

Breast cancer is the most common form of cancer in women in the world with more than 400,000 deaths each year worldwide. The aim of this study is to compare population frequencies of alleles and genotypes of polymorphic variants of BRCA1 and BRCA2 genes associated with breast cancer risk in an ethnically homogenous Kazakh population with previously studied world populations. The material of the study was DNA isolated from peripheral blood of the enrolled population control group, represented by 1800 conditionally healthy individuals of Kazakh ethnicity. The DNA extraction was possible with the use of M-PVA magnetic particle separation method on the Prepito (PerkinElmer) automatic analyser for extraction of Chemagic Prepito (Wallac, Finland) nucleic acids using the PrepitoDNACytoPure reagent kit. Statistical calculations of allele and genotype frequencies, significance tests, and non-parametric χ2 analysis were carried out using PLINK software. The results favour for the high genetic heterogeneity of the studied polymorphisms, which reflects the specifics of the Kazakh population structure resulted from complex evolutionary and migration processes, as well as the median geographic location between the populations of Asia and Europe. Knowledge of the spectrum and frequency of mutations in BRCA1 and BRCA2 genes predisposing to breast cancer, which are present in varying frequencies in the Kazakh population, will provide a more effective approach to the screening protocol and allow for a faster, less expensive and more accessible genetic testing strategy for the Kazakhstan citizens.

USE OF THE DYNAMIC LIGHT SCATTERING TO ASSESS THE EFFICIENCY OF SEPARATION OF SUSPENDED AND COLLOIDAL PARTICLES IN RIVER WATERS BY FILTRATION AND CENTRIFUGATION

Link for citation: Shulkin V.M. Use of the dynamic light scattering to assess the efficiency of separation of suspended and colloidal particles in river waters by filtration and centrifugation. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 10, рр. 88-97. In Rus. The relevance of the study is stipulated by the need to control the completeness and accuracy of the separation of suspended and colloidal particles using filtration and centrifugation methods during the analysis of the chemical composition of river waters. The main goal: to test and evaluate the possibility of using the method of dynamic light scattering to monitor the effectiveness of separation of suspended and colloidal particles of river waters by filtration and centrifugation. Objects: waters of typical rivers of the south of the Russian Far East with different levels of anthropogenic load and landscape structure of watersheds, which leads to obvious variations in the concentration levels of dissolved, colloidal and suspended forms of chemical elements in rivers, as well as to different content and grain size composition of suspended matter. Methods: measurement of the dynamic light scattering intensity, including its size distribution, using the Photocor COMPACT Z device in unfiltered samples of river waters, as well as in the filtrates through capsule and membrane filters with varying degrees of clogging, and in the supernatants obtained under various conditions. At the same time, the sum content of suspended and coarse-colloidal particles in the initial samples of river waters was determined gravimetrically after filtration through membrane filters with a pore size of 0,45 μm. Results. The dynamic light scattering intensity in unfiltered river waters demonstrates a significant linear dependence on the suspension content in the range of 5–150 mg/l, determined gravimetrically. In filtrates via a membrane or capsule filter of 0,45 μm, the dynamic light scattering intensity does not depend on the suspension content in the unfiltered samples. Analysis of the size distribution of dynamic light scattering intensity in the unfiltered samples, and in the filtrates confirms the removal efficiency of particles larger than 0,45 μm both at the filtration through membrane or capsule filters, and at the centrifugation for 30' at 4500 rpm. Dynamic light scattering allows characterizing the efficiency of separation of suspended and coarse-colloidal particles in river waters from thin colloids and dissolved forms using membrane and capsule filters, as well as centrifugation. Thus, it becomes possible to control the processes of filters clogging and choose the optimal method for separation of suspended and colloidal particles at the chemical analysis of river waters.

Numerical analysis of solid particle erosion caused by slurry in dredging pipelines based on a particle separation method

A new numerical procedure is proposed to analyse solid particle erosion caused by slurry. The procedure works involves two mechanisms. First, high-concentration particles are considered as a continuous granular phase and tracked through the Eulerian–Eulerian two-fluid method. Second, the continuous granular phase near the pipe wall is converted into discrete incident and rebound particles by a particle separation method. The procedure is validated through comparison with experimental data available in the literature. Additionally, the performance and efficiency of the new method are compared with those of the dense discrete phase method and the discrete element method.

Microfluidic separation of particles by synergistic effect of geometry-induced hydrodynamics and magnetic field

Microfluidic combined with magnetic field have been demonstrated to be the promising solutions for fast and low-damage particles separation. However, the difficulties in the precise layout of magnets and accurate prediction of particle trajectories lead to under and over separation of target particles. A novel particle separation lab-on-chip (LOC) prototype integrated with microstructures and micropolar arrays is designed and characterized. Meanwhile, a numerical model for the separation of magnetic particles by the synergistic effect of geometry-induced hydrodynamics and magnetic field is constructed. The effect of geometry and magnetic field layout on particle deflection is systematically analyzed to implement accurate prediction of particle trajectories. It is found that the separation efficiency of magnetic particles increased from 50.2% to 91.7% and decreased from 88.6% to 85.7% in the range of depth factors from 15 µm to 27 µm and width factors from 30 µm to 60 µm, respectively. In particular, the combined effect of the offset distance of permanent magnets and the distance from the main flow channel exhibits a significant difference from the conventional perception. Finally, the developed LOC prototype was generalized for extension to arbitrary systems. This work provides a new insight and robust method for the microfluidic separation of magnetic particles.

Tunable magnetophoretic method for distinguishing and separating wear debris particles in an Fe-PDMS-based microfluidic chip.

Wear debris analysis provides an early warning of mechanical transmission system aging and wear fault diagnosis, which has been widely used in machine health monitoring. The ability to detect and distinguish the ferromagnetic and nonmagnetic debris in oil is becoming an effective way to assess the health status of machinery. In this work, an Fe-poly(dimethylsiloxane) (PDMS)-based magnetophoretic method for the continuous separation of ferromagnetic iron particles by diameter and the isolation of ferromagnetic particles and nonmagnetic particles with similar diameter by type is developed. The particles experience magnetophoretic effects when passing through the vicinity of the Fe-PDMS where the strongest gradient of the magnetic fields exists. By choosing a relatively short distance between the magnet and the sidewall of the horizontal main channel and the length of Fe-PDMS with controlled particles flow rate, the diameter-dependent separation of ferromagnetic iron particles, that is, smaller than 7µm, in the range of 8-12µm, and larger than 14µm, and the isolation of ferromagnetic iron particles and nonmagnetic aluminum particles based on opposite magnetophoretic behaviors by types are demonstrated, providing a potential method for the detection of wear debris particles with a high sensitivity and resolution and the diagnostic of mechanical system.

Sorting of chiral active particles by a spiral shaped obstacle

Sorting of chiral particles by obstacles often relies on the chiral symmetry breaking of the patterns. We proposed a method for the chiral separation of chiral active particles in a two-dimensional square box where exists a spiral shaped obstacle. With the chirality of circular motion coupling to chiral features in the spiral environment, the mixed chiral particles can be separated and selectively trapped by the spiral shaped obstacle. We found that the mixed particles can be completely separated for the optimal angular speed and self-propulsion speed of active particles. Our results can be exploited to capture or sort chiral active particles with specific parameters.

Deterministic Lateral Displacement (DLD) Analysis Tool Utilizing Machine Learning towards High-Throughput Separation.

Deterministic lateral displacement (DLD) is a microfluidic method for the continuous separation of particles based on their size. There is growing interest in using DLD for harvesting circulating tumor cells from blood for further assays due to its low cost and robustness. While DLD is a powerful tool and development of high-throughput DLD separation devices holds great promise in cancer diagnostics and therapeutics, much of the experimental data analysis in DLD research still relies on error-prone and time-consuming manual processes. There is a strong need to automate data analysis in microfluidic devices to reduce human errors and the manual processing time. In this work, a reliable particle detection method is developed as the basis for the DLD separation analysis. Python and its available packages are used for machine vision techniques, along with existing identification methods and machine learning models. Three machine learning techniques are implemented and compared in the determination of the DLD separation mode. The program provides a significant reduction in video analysis time in DLD separation, achieving an overall particle detection accuracy of 97.86% with an average computation time of 25.274 s.

Population features of alleles and genotypes frequency distribution of polymorphic genetic markers of antipsychotic medications pharmacokinetics in the Kazakh population.

The presented article is relevant, as the main goals of schizophrenia treatment are to achieve a response to psychopharmacotherapy, reduction and stabilization of psychopathological symptoms, qualitative remission, which in general implies the creation of a stable quality of life for the patient. The purpose of the study was to evaluate the population features of the frequency distribution of alleles and genotypes of polymorphic genetic variants of according to genome-wide association studies analysis of pharmacokinetics-associated antipsychotic medications, in an ethnically homogeneous Kazakh population. The research material was deoxyribonucleic acid (DNA) isolated from the peripheral blood of 1,800 conditionally healthy persons of Kazakh nationality. DNA isolation was carried out by the magnetic polyvinyl alcohol magnetic particle separation method. The analysis of the frequency distribution of the studied genotypes in the Kazakh population showed their compliance with the Hardy-Weinberg equilibrium for all studied polymorphisms (p > .05). The obtained results showed that CYP2C19 (rs4244285, rs4986893) polymorphisms occurs in Kazakhs significantly more often than European and a number of Asian populations, which significantly affects the decrease in effectiveness and increases the risk of side complications during therapy with antipsychotic medications in the Kazakh population.

Separation method of particles based on electromagnetic coupling

This paper investigates an approach for particle matter (PM) separation with electromagnetic field coupling. In consideration of electric and magnetic fields, linear and nonlinear dynamics models of PM separation are established. Simultaneously, this model considers the response of different diameters and velocities of PM to the change of the dynamic model, and the coupling effect of electromagnetic field is used to separate particles. Numerical results present that PM diameter, magnetic field drag, and strength play an important role in the separation of the PM matter. Moreover, with the increase of flux density or the decrease of drag force, the PM separation displacement will grow. Changing the flux density is better than changing the drag force to separate the particles. Following the growth of particle diameter and magnetic flux density, the particle changes from linear motion to spiral motion, and the final particle velocity reaches a stable state after attenuation. In addition, considering the changes of drag force and magnetic field, when drag decrease and magnetic flux density increase, the separation effect gradually becomes better, and the optimal separation distance reaches the decimeter level. However, in most cases, the PM displacement response is small. The work has certified the proposed separation method is feasible by decreasing drag and enhancing magnetic flux density.

Nonnegligible nano-confinement effect on solvent-mediated interactions between nanoparticles

Separating nanoparticles (NPs) by means of microfluidics represents a promising method. One of the associate challenges is how to regulate the interactions between NPs in confined solvents for avoiding particle aggregation. To tackle this challenge, herein we conduct a theoretical study to interpret the confinement effects on the potential of mean force between two NPs in nanochannels. By using the classical density functional theory, the effects of pore width, wall wettability, NP size, and solvent-NP interactions are unraveled. It is found that the nano-confinement can noticeably enhance the short-ranged attraction between NPs, and the attraction strength can be moderated by enlarging pore size, making wall solvophobic, shrinking NP size, and widening the range of solvent-NP interaction. This study provides a theoretical guidance towards the development of efficient particle separation method in nanochannel-based devices.

Numerical simulation of critical particle size in asymmetrical deterministic lateral displacement

Microfluidics devices are widely used for particle separation. Deterministic Lateral Displacement (DLD) is a passive method for particle separation. DLD devices mainly separate particles based on their sizes. There are two main modes of movement in DLD arrays; the small particles move in a zigzag path, and the larger particles separate in the displacement mode. It is therefore important to estimate the critical particle size for the transition of modes before the fabrication of DLD devices. Asymmetry in the design of the arrays can affect the fluid behavior and the critical particle size. In this study, we investigate the effects of the asymmetry caused by changing the downstream gap size to the lateral gap size ratio on the fluid behavior and particle trajectories in DLD devices. We used two dimensional (2D) Finite Element Method (FEM) to study the variations in the flow lane's widths and combined the fluid analysis with structural mechanics to model the contact between the particles and the posts in DLD arrays. We simulated the spherical particles' trajectories with diameters ranging from 1.4 to 19.2 μm in circular post DLD arrays with a lateral gap size of 20μm. In contrast to the previous works, in these simulations, the effect of particle movement on the fluid flow profiles was considered. We evaluated the particle movement mode in seven different values of the downstream gap size to the lateral gap size ratio (ranging from 0.5 to 2) and eight different row shift fraction (ranging from 0.025 to 0.3). Our simulations showed that increasing the value of the downstream gap while the lateral gap is fixed increases the veering flow rate and width. By finding the particle with the largest diameter in the zigzag mode and the particle with the smallest diameter in the displacement mode, we estimated the critical particle diameter for each value of shift fraction in different values of the downstream gap to the lateral gap size ratio. Using these data, a curve was fitted for predicting the critical particle diameter in each ratio. Finally, a more general form of the formula for the critical particle diameter was proposed, which considers an extra parameter compared to the previous ones. The results of this study can lead to a better understanding of DLD devices' functions and, thus, save time and costs for better designs and experiments.

Detailed modeling of solids separation by microsieving in a rotating belt filter: Explicit effect of particle size, mesh size, and polymer dose

Microsieving by rotating belt filters is an engineered fractionation method for particle separation from wastewater that can be used as an alternative to primary clarification due to its smaller footprint and lower total cost of ownership. Because of the multiscale nature of the filtration processes involved, and the interdependent variables controlling performance and the system design, the availability of verified and comprehensively validated models that, based on fundamental principles, can explicitly capture the effect of particle size, mesh size and polymer dose are essential for performance optimization and scale-up. In this paper, a detailed microsieving filtration model was derived by extending Darcy’s law to a dual-layer dynamic framework whose predictions were validated against batch (column) and continuous flow (RBF pilot) experimental data. The ability of the microsieving model to accurately capture observed trends confirmed that the model formulation, derived from column experiments, were sufficiently accurate and flexible to capture the relevant physics involved, with a relative error in performance scale up (from column to pilot) of 33% and 14% for filter capacity and effluent total suspended solids, respectively. Upon further calibration against pilot data, the relative error was reduced to 9% and 5%, respectively, indicating the suitability of the model structure in further adapting to filtration process conditions occurring at pilot scale. Finally, the calibrated model was used to derive guidance for future pilot studies. It was determined that, under naturally varying influent conditions, at least 8 h of continuous pilot data, with sampling frequency of at least 15 min for filter capacity and suspended solids concentration, were necessary for a satisfactory estimate of the model parameters.

Analysis of the mixing efficiency of the components of the iron-phosphate mixture in the dry state

The results of researches of influence of time of mixing of initial components in a dry condition on degree of assimilation of iron-containing component of forming and core iron-phosphate cold-hardening mixes are presented. The percentage of assimilation of the dispersed iron-containing component after each minute of mixing in laboratory runners with a total mixing time of 15 minutes was determined experimentally. Using the original method of particle separation, under the microscope were separated scale particles that were not assimilated (not distributed on the surface of the sand), and weighed them. The dependences of the degree of assimilation of the metal component of the iron-phosphate mixture on the mixing time at different initial contents are obtained. It is shown that the highest degree of absorption of the iron-containing component of iron-phosphate mixtures is achieved by mixing the components of the mixture for the first four to five minutes. Then this figure begins to decrease as the grains begin to collapse under the action of the rolls of the runners, and the forces of electrostatic interaction between the surfaces of the grains and the dispersion medium are reduced compared to the forces of mutual gravity between the dispersed particles of iron-containing component of the mixture. Based on the analysis of theoretical positions and the results of experimental studies, the assumption is made about the possibility of adjusting the conditions and parameters of solidification of phosphate binder systems, in particular using iron-containing filler of a certain dispersion and mixing the components in the dry state for some time. It is known that for mixing the components and assimilation of the required part of the iron-containing component of the mixture uses a significant amount of energy (depending on the type of unit used). To reduce the energy consumption of this process, the urgent task is to determine the degree of assimilation of the iron-containing component of phosphate cold-hardening mixtures in their manufacture by mixing the components in the dry state. Keywords: iron-phosphate cold-hardening mixture, mixing in the dry state, interaction, adhesion, experiment, research, dependence

Purification of Murine Gammaherpesvirus 68 With Use of Differential Centrifugation

Abstract The method for separation of viral particles in a concentrated form from the environment is called virus purification. Viruses are required to be purified for a range of studies in which it is necessary to distinguish the properties or structure of a virus from the host cells or culture media, including analysis of viral polypeptide structures and membrane glycoprotein function. Our objective was to purify murine gammaherpesvirus 68 (MHV-68, MuHV-4) using the centrifuge, equipment and other materials available in our laboratory. After infection of baby hamster kidney 21 (BHK-21) cells with MHV-68 with the multiplicity of infection (MI) of 0.01 and following virus multiplication, we repeatedly froze and thawed the cell culture to disrupt the cells and release the virus particles into the culture medium. We used low-speed centrifugation (3000 rpm at 4°C) to separate the viral particles from cell debris. Subsequently, we transferred the supernatant containing virus particles to a fresh centrifuge tube and centrifuged at a speed of 8000 rpm (8801 g) and 11,000 rpm (=16,639 g) and at 4°C. We tested different centrifugation durations of 2, 4, 6 and 8 hours. To evaluate the quality of the obtained purified MHV-68 virus by this method and compare it to purified MHV-68 sample acquired by conventional ultracentrifugation on sucrose cushion (30%, w/v), we used the SDS-PAGE separation method using a 4%–20% (w/v) and 6%–14% (w/v) gradient gel. We obtained the best results with 6-hour-long centrifugation at 11,000 rpm. In conclusion, we managed to optimise virus purification method using the equipment available in our laboratory and prepared purified MHV-68 virus in sufficient concentration for determination of MHV-68 virus proteins.

Deterministic Lateral Displacement: Challenges and Perspectives.

The advent of microfluidics in the 1990s promised a revolution in multiple industries from healthcare to chemical processing. Deterministic lateral displacement (DLD) is a continuous-flow microfluidic particle separation method discovered in 2004 that has been applied successfully and widely to the separation of blood cells, yeast, spores, bacteria, viruses, DNA, droplets, and more. Deterministic lateral displacement is conceptually simple and can deliver consistent performance over a wide range of flow rates and particle concentrations. Despite wide use and in-depth study, DLD has not yet been fully elucidated or optimized, with different approaches to the same problem yielding varying results. We endeavor here to provide up-to-date expert opinion on the state-of-art and current fundamental, practical, and commercial challenges with DLD as well as describe experimental and modeling opportunities. Because these challenges and opportunities arise from constraints on hydrodynamics, fabrication, and operation at the micro- and nanoscale, we expect this Perspective to serve as a guide for the broader micro- and nanofluidic community to identify and to address open questions in the field.

Protein corona formation on particles in bovine synovial fluid and in a rat knee model of osteoarthritis

Purpose: In osteoarthritis (OA), molecular changes occur throughout the joint, causing changes in the joint milieu. Micro- and nanoparticles can be used to characterize these molecular changes. Specifically, proteins within the synovial fluid non-specifically adsorb onto the surface of particles. As such, changes in the protein corona formation on the particle surface may relate to molecular changes in OA. While protein corona formation is commonly studied in serum and cell culture media, it has not been assessed in OA animal models. In this study, protein corona formation was assessed in bovine synovial fluid and in a rat OA model. Methods: First, commercially available, magnetic microparticles (Dynabeads) were placed in bovine synovial fluid and separated using magnetic separation or centrifugation. The resulting protein corona was characterized using mass spectrometry. Then, 12 male and 12 female Lewis rats (9 weeks old) received a unilateral, simulated medial collateral ligament and meniscal injury. At 2, 5, or 8 weeks post-surgery, operated and contralateral limbs were injected with magnetic particles (n=4 per sex). After a 4-hour incubation, animals were euthanized, particles were recovered from the joint, and the protein corona was characterized using an Orbitrap Fusion Mass Spectrometer. Results: In bovine synovial fluid, a total of 116 proteins were identified, of which 35 were different between magnetic separation and centrifugation. In the rat OA model, 454, 464, and 342 proteins were identified at 2, 5, and 8 weeks post-surgery, respectively. Of the identified proteins on the particle surface, 35, 59, and 13 were different between the operated and contralateral limbs at 2, 5, and 8 weeks, respectively (p < 0.05, see Figure 1). Using principal component analysis, changes in the protein corona were found to relate with OA progression. Conclusions: Data from the bovine synovial fluid demonstrated that the protein corona that forms on the particle surface varies based on the method of particle separation from synovial fluid. Moreover, the in vivo data demonstrates that the protein corona layer on a particle surface changes at various stages of OA progression. Understanding how the particle-protein interface changes as a function of disease progression may be useful for biomarker discovery and informing the design of intra-articular drug delivery vehicles.