Magnetic Separation Device Research Articles

Surfactant-mediated colorimetric assay assisted with in-situ rolling circle amplification on magnetic beads

Gold nanoparticles (AuNPs) with localized surface plasmon resonance effect have been widely used for colorimetric detection based on the interparticle plasmon coupling during AuNPs aggregation. However, it is still challenging to develop portable and quantitative methods with good sensitivity and excellent selectivity. In this study, a smartphone-based colorimetric assay is developed on the principle of surfactant-mediated AuNPs aggregation assisted with rolling circle amplification (RCA) on magnetic beads (MBs). The detection of adenosine is demonstrated as an example. The cetyl trimethyl ammonium bromide (CTAB) causes the negatively charged AuNPs to aggregate, which results in the color change from red to blue. When adenosine is in solution, the RCA process is triggered on the MBs because of specific adenosine-aptamer recognition, resulting in prolongation of single-stranded nucleic acid (ssDNA). The solution color remains red due to the electrostatic interaction between CTAB and ssDNA. Using this method, the limit of detection (LOD) for adenosine can be as low as 16 pM. Besides, it also works well in human serum. In addition, a portable device integrated with in-situ RGB analysis software is developed for the detection with a smartphone. This study offers a new strategy to improve the sensitivity and selectivity for the AuNPs-based colorimetric assay, taking advantages of specific aptamer recognition, in-situ RCA on MBs, magnetic separation, and smartphone-based portable device.

A portable 3D-printed pretreatment device combined with graded lateral flow assay for detection of S. aureus

There is a need for facile yet reliable bacterial pretreatment and signal-graded strategies for current pathogens' point-of-care testing (POCT). Herein, we present a multifunction and portable 3D-printed magnetic separation device with graded lateral flow assay (LFA) for semi-automated pretreatment and rapid detection of Staphylococcus aureus (S. aureus) in food. The 3D-printed pretreatment device allows purification and enrichment of the palladium@platinum nanoparticles (Pd@Pt NPs)-antibody-S. aureus complex. The recovery rate was 81.7–96.1% in actual food samples. Pd@Pt NPs-mediated signal amplification immunoassay achieved graded detection of S. aureus, reducing the detection limit from 103 CFU/mL to 102 CFU/mL, corresponding to the highest safety limit value (M) and acceptable level limit value (m) of S. aureus in many countries and organizations, respectively. This study paves the way for cost-effective and sensitive POCT with multiplexing potential in applications ranging from pretreatment of samples in the complex matrix as well as foodborne pathogens graded and rapid analysis.

Development of the magnetic separation device for surface cracks of delinted cottonseed

Development of the magnetic separation device for surface cracks of delinted cottonseed

Synthesize and tuneable structure, optical, photoluminescence, and magnetic properties of novel SrSnO3/Fe3O4nanocomposites for promising applications

In the current work, a simple wet chemical co-precipitation strategy has been effectively used to synthesize the novel SrSnO3/Fe3O4nanocomposites.The synergistic effect of magnetite on SrSnO3 has been explored by examining the chemical nature of the samples' surfaces, structures, and morphology using XPS, XRD, HRTEM, and FESEM. According to XPS measurements, the Sr2+, Sn4+, Fe2+, 3+, and O states are present in the nanocomposites. XRD reveals nanocomposite oxide materials composed of well-supported nanocrystalline phases from both fundamental oxides. The particles formed were nanocubes, almost round, spherical, tetrahedron, and octahedron-shaped grains, according to HRTEM and SEM analysis. Using UV analysis, the bandgap of a nanocomposite was significantly reduced from 3.7 eV to 2.06 eV.The emission peak has a low intensity, suggesting that there is increased photocatalytic activity in the energetic isolation of electron-hole pairs, which is detected by PL spectroscopy. It was noted that the saturation magnetization values of nanocomposites (8.594, 10.71, 19.13 emu/g) grew with the increase in magnetite content in nanocomposites, which is dominant to other magnetic photocatalysts and indicates enhanced magnetic response which is identified by VSM. This promising nanocomposite could be used in magnetic separation, photocatalysis, and multicolor lighting devices.

An Automated Magnetic Separation Device Coupled with a Fluorescent Biosensor for Detection of Antibiotic Residues

HighlightsA practical magnetic separation device was designed, fabricated, and evaluated for enrofloxacin detection.Coupled with a fluorescent biosensor, the device could automatically process a sample in 50 min.The device performed incubation and magnetic separation using a pipette method.The device has the advantages of low-cost and feasibility for on-site detection.Abstract. Antibiotic residues have been a continuing concern in food safety, raising a great issue in human health. For rapid detection of antibiotics, an automated device was developed that can capture and separate a target analyte based on immunomagnetic beads. This automated separation device is suitable for separating the magnetic beads in a preprocessing step, with liquid transfer and magnetic enrichment functions. The device was combined with a fluorescent biosensor to simplify the cumbersome pretreatment of enrofloxacin. In our experiments, enrofloxacin in water samples was used as the detection object, and the entire process could be completed in less than 50 min with automated operation. The lower limit of detection reached 54 ng mL-1 (S/N = 3). The fluorescent biosensor has been enhanced with this automated separation device for more sensitive rapid detection of antibiotic residues in the food supply chain and environment. Keywords: Antibiotic detection, Automation, Fluorescent biosensor, Immunomagnetic separation, Sample pretreatment.

Force index computation for a magnetic separator based on permanent magnet

Magnetic separation devices are widely used to separate tramp of iron from a specific feed of materials. Many industries rely on those devises and the variety of technological solution depend mainly on the characteristic of the tramp to be separated. In this paper, main characteristics of low intensity magnetic separation devices based on permanent magnets for dry feed are considered to evaluate force index computation.

Model of particle accumulation on matrices in transverse field pulsating high gradient magnetic separator

The static buildup model of particle on single wires (SBM-sw), illustrating the effect of these influencing parameters such as applied magnetic induction, fluid velocity and wires size on particle accumulation, plays a dominant role in instructing the design of a high gradient magnetic separation (HGMS) device. However, in a real separation chamber of HGMS filled with piles of matrices, the changes of hydrodynamic due to gap shrinkage of matrices disturb particle accumulation. When slurry within the matrix is exposed to pulsation, this disturbance is intensified. Consequently, compared to SBM-sw, the model of magnetic particle accumulation on double wires (SBM-dw) is supposed more suitable to reveal the processing of magnetic particle accumulation on matrices. In this article, SBM-sw and SBM-dw of a transverse field pulsating HGMS separator (TPHGMS) was presented based on force equilibrium. The effect of pulsating slurry, wire spacing and applied magnetic induction on particle accumulation of the TPHGMS was investigated and discussed with calculating the buildup profiles under specific parameters. Pulsating slurry directly impinges the regions of paramagnetic particle capture and leads to sharp decrease of particle buildup under high frequency. Enlarging wire spacing or decreasing pulsating frequency can weaken the impact of slurry and slow down the decrease of particle buildup. In addition, increasing applied magnetic induction within a certain range can also significantly increase particle buildup. Finally the SBM-dw model was compared with a series of experiments. Results indicated that experimental particle buildup weights agreed with the calculated particle buildup weights of SBM-dw which provides better authenticity to understand and predict the performance of the TPHGMS.

Magnetic Separation on a New Level: Characterization and Performance Prediction of a cGMP Compliant "Rotor-Stator" High-Gradient Magnetic Separator.

The growing market of biopharmaceuticals and the constant developments in upstream fermentation have generated a strong demand for new downstream purification methods. Magnetic separation in combination with functional magnetic particles has been known for many years as a promising candidate for a direct capturing tool in protein purification but the lack of suitable GMP-compliant purification equipment has prevented the launch of this technology in large scale bioprocessing. To tackle this bottle-neck, the principle of a "rotor-stator" high-gradient magnetic separator is fully redesigned to meet the rigorous requirements of modern cGMP biotechnology purification processes. In order to fulfill regulatory requirements, the separation chamber is reengineered to allow effective cleaning and sterilization in place while maintaining excellent separation capacities and efficiencies. Two kinds of commercially available magnetic particles are used to validate key performance data and determine system related parameters in order to calculate process performance figures for process optimization of the new magnetic separation device. With separation capacities of over 400 g of magnetic particles per liter of separation chamber volume and separation efficiencies as well as recovery rates over 99%, the system is able to process more than 200 l crude feedstock per day and capture more than 1.6 kg target compounds.

Magnetic separation on a new level: first cGMP compliant magnetic separation device, cleaning validation studies and protein purification optimization

Magnetic separation on a new level: first cGMP compliant magnetic separation device, cleaning validation studies and protein purification optimization

Study on Magnetic Separation Device for Scale Removal From Feed-Water in Thermal Power Plant

To improve thermal power plant efficiency, we proposed a water treatment system with a high gradient magnetic separation (HGMS) system using a superconducting magnet, which is applicable in high-temperature and high-pressure conditions. This is a method to remove the scale from feed-water utilizing magnetic force. One of the issues for practical use of the system is how to extend the continuous operation period. In this paper, we succeeded in solving the problem by eliminating the deviation of captured scale quantity by each filter. In fact, in the HGMS experiment using the solenoidal superconducting magnet, it was shown that a decrease in separation rate and an increase in pressure loss were prevented, and the total quantity of captured scale increased by proper filter design. The design method of the magnetic filter was proposed and will be suitable for long-term continuous scale removal in the feed-water system of the thermal power plant.

Magnetic adsorption separation (MAS) process: An alternative method of extracting Cr(VI) from aqueous solution using polypyrrole coated Fe 3 O 4 nanocomposites

Abstract A simple pilot-scale magnetic adsorption separation (MAS) device was designed, fabricated and tested in treating aqueous solution stream laden with highly toxic and mobile hexavalent chromium [Cr(VI)] ions using super-paramagnetic crystalline polypyrrole–magnetite nanocomposite (PPy–Fe3O4 NC) as a mobile scavenger. In the first experiment, the kinetics of Cr(VI) adsorption on PPy–Fe3O4 NC containing three different quantities of Fe3O4 nanoparticles were explored in a continuously stirred tank reactor (CSTR) operated in a batch mode. Thereafter, combined adsorption and magnetic separation process studies were conducted in semi-continuous and continuous operations modes whereby Cr(VI) loaded PPy–Fe3O4 NC particles were continuously isolated from the treated stream using a rare-earth permanent magnet. In the adsorption and magnetic separation systems, Cr(VI) removal and magnetic separation efficiency were used as key performance indicators. Results on batch adsorption kinetic studies showed that the quantity of Fe3O4 nanoparticles in the PPy–Fe3O4 NC influenced Cr(VI) removal whereby equilibrium uptakes of 119 mg/g, 109 mg/g and 103 mg/g were achieved using 50.4%, 58.5% and 40.3% Fe3O4 loaded NCs, respectively. Meanwhile, for semi-continuous operations, a decrease in initial Cr(VI) concentration in the reactor and an increase in the quantity of Fe3O4 nanoparticles in the NCs resulted in improved magnetic separation efficiency. Moreover, the introduction of stainless steel (SS) wool in the separation chamber enhanced the entire separation process. Finally, results obtained from a continuously operated MAS system revealed that it is possible to achieve 100% Cr(VI) removal when the residence time was set at 30 min, at a flow rate of 0.2 L/min. At those prevailing conditions, the magnetic separation efficiency was 92%.

Investigation of exploitation of iron placer deposit effects on physicochemical properties of agricultural dryland soils, Baklik Basin, Markazi Province, Iran

Consumption rate of mineral resources continuously increases with industrialization and urbanization, as well as with population growth. Previous explorations of iron (Fe) placer deposits in the Baklik Basin of Markazi Province in Iran showed that a high level of Fe placer deposits exist in the region that may be considered a valuable mining deposit. To investigate effects of Fe placer deposits9 exploitation on physicochemical characteristics of dryland soils, the topsoil (0 to 30 cm [0 to 11.8 in]) was cut and moved to one corner of the pilot site (2 ha [4.9 ac]) by bucket loader. A magnetic separation device was used to separate magnetite substances from the soil. After magnetite separation, the treated soil was returned to the site and leveled, then deeply plowed to mix with the underlying soil. Contour plowing or plowing across slope and along elevation line were carried out to mitigate soil erosion. Analysis of physicochemical characteristics of several soil samples and study of soil, water, and plant interactions in experimental plots show that there are no significant differences between treated and untreated soils. However, it is necessary to carry out soil conservation practices in the treated parcels to avoid wind and water erosions during dry and wet seasons.

Collection of airborne particles by a high-gradient permanent magnetic method

We report on the use of magnetic force in collection of airborne particles by a high-gradient permanent magnetic separation (HGPMS) device. Three aerosol particles of different magnetic susceptibility (NaCl, CuO, and Fe3O4) were generated in the electrical mobility size range of 10–200nm and were used to study HGPMS collection. One HGPMS matrix element, made of stainless steel wool, was used in the device configuration. Three flow rates were selected to simulate the environmental wind speeds of interest to the study. Magnetic force was found to exhibit an insignificant effect on the separation of NaCl particles, even in the HGPMS configuration. Diffusion was a major mechanism in the removal of the diamagnetic particles; however, diffusion is insignificant under the influence of a high-gradient magnetic field for paramagnetic or ferromagnetic particles. The HGPMS showed high-performance collection (>99%) of paramagnetic CuO and ferromagnetic Fe3O4 particles for particle sizes greater than or equal to 60nm. As the wind speed increases, the influence of the magnetic force weakens, and the capability to remove particles from the gas stream diminishes. The results suggest that the HGPMS principle could be explored for development of an advanced miniaturized passive aerosol collector.

Most-Probable-Number Loop-Mediated Isothermal Amplification-Based Procedure Enhanced with K Antigen-Specific Immunomagnetic Separation for Quantifying tdh+Vibrio parahaemolyticus in Molluscan Shellfish

Although thermostable direct hemolysin-producing (tdh(+)) Vibrio parahaemolyticus is the leading cause of seafood-borne gastroenteritis, the enumeration of tdh(+) V. parahaemolyticus remains challenging due to its low densities in the environment. In this study, we developed a most-probable-number (MPN)-based procedure designated A-IS(1)-LAMP, in which an immunomagnetic separation (IMS) technique targeting as many as 69 established K antigens and a loop-mediated isothermal amplification (LAMP) assay targeting the thermostable direct hemolysin (tdh) gene were applied in an MPN format. Our IMS employed PickPen, an eight-channel intrasolution magnetic particle separation device, which enabled a straightforward microtiter plate-based IMS procedure (designated as PickPen-IMS). The ability of the procedure to quantify a wide range of tdh(+) V. parahaemolyticus levels was evaluated by testing shellfish samples in Japan and southern Thailand, where shellfish products are known to contain relatively low and high levels of total V. parahaemolyticus, respectively. The Japanese and Thai shellfish samples showed, respectively, relatively low (< 3 to 11 MPN/10 g) and considerably higher (930 to 110,000 MPN/10 g) levels of tdh(+) V. parahaemolyticus, raising concern about the safety of Thai shellfish products sold to domestic consumers at local morning markets. LAMP showed similar or higher performance than conventional PCR in the detection and quantification of a wide range of tdh(+) V. parahaemolyticus levels in shellfish products. Whereas a positive effect of PickPen-IMS was not observed in MPN determination, PickPen-IMS was able to concentrate tdh(+) V. parahaemolyticus 32-fold on average from the Japanese shellfish samples at an individual tube level, suggesting a possibility of using PickPen-IMS as an optional tool for specific shellfish samples. The A-IS(1)-LAMP procedure can be used by any health authority in the world to measure the tdh(+) V. parahaemolyticus levels in shellfish products.

Isolation and mutational analysis of circulating tumor cells from lung cancer patients with magnetic sifters and biochips

Detection and characterization of circulating tumor cells (CTCs) may reveal insights into the diagnosis and treatment of malignant disease. Technologies for isolating CTCs developed thus far suffer from one or more limitations, such as low throughput, inability to release captured cells, and reliance on expensive instrumentation for enrichment or subsequent characterization. We report a continuing development of a magnetic separation device, the magnetic sifter, which is a miniature microfluidic chip with a dense array of magnetic pores. It offers high efficiency capture of tumor cells, labeled with magnetic nanoparticles, from whole blood with high throughput and efficient release of captured cells. For subsequent characterization of CTCs, an assay, using a protein chip with giant magnetoresistive nanosensors, has been implemented for mutational analysis of CTCs enriched with the magnetic sifter. The use of these magnetic technologies, which are separate devices, may lead the way to routine preparation and characterization of "liquid biopsies" from cancer patients.

Deproteination of serum samples for LC–MS/MS analyses by applying magnetic micro-particles

ObjectivesInvestigation of the practicability and performance of a magnetic micro-particle based method for protein depletion of serum samples, preceding the quantitative analysis of small molecules by LC–MS/MS. Design and methodsA commercially available kit including a protein denaturation reagent and functionalized magnetic particles together with a magnetic separator device was tested by addressing the quantification of amiodarone in serum as an exemplary analyte by LC–MS/MS with on-line SPE. A standard method validation protocol was applied. ResultsThe sample preparation protocol was found to be convenient, straightforward and robust. Validation data characterized the entire analytical method – combining particle-based protein depletion and two-dimensional chromatography – as compatible with the analytical needs regarding selectivity, accuracy (102–106%), linearity (r2≥0.99), reproducibility (CV<7%), and control of ion suppression. ConclusionsSince this novel approach of sample preparation does neither require centrifugation nor the technically demanding application of positive or negative pressure, as in conventional solid phase extraction protocols, it seems highly attractive for developing fully automatized preparation systems for LC–MS/MS analyzers.

Electrosteric Stabilization and Its Role in Cooperative Magnetophoresis of Colloidal Magnetic Nanoparticles

A detailed study on the conflicting role that colloid stability plays in magnetophoresis is presented. Magnetic iron oxide particles (MIOPs) that were sterically stabilized via surface modification with poly(sodium 4-styrene sulfonate) of different molecular weights (i.e., 70 and 1000 kDa) were employed as our model system. Both sedimentation kinetics and quartz crystal microbalance with dissipation (QCM-D) measurements suggested that PSS 70 kDa is a better stabilizer as compared to PSS 1000 kDa. This observation is mostly attributed to the bridging flocculation of PSS 1000 kDa decorated MIOPs originated from the extended polymeric conformation layer. Later, a lab-scale high gradient magnetic separation (HGMS) device was designed to study the magnetophoretic collection of MIOPs. Our experimental results revealed that the more colloidally stable the MIOP suspension is, the harder it is to be magnetically isolated by HGMS. At 50 mg/L, naked MIOPs without coating can be easily captured by HGMS at separation efficiency up to 96.9 ± 2.6%. However, the degree of separation dropped quite drastically to 83.1 ± 1.2% and 67.7 ± 4.6%, for MIOPs with PSS 1000k and PSS 70k coating, respectively. This observation clearly implies that polyelectrolyte coating that was usually employed to electrosterically stabilize a colloidal system in turn compromises the magnetic isolation efficiency. By artificially destroying the colloidal stability of the MIOPs with ionic strength increment, the ability for HGMS to recover the most stable suspension (i.e., PSS 70k-coated MIOPs) increased to >86% at 100 mM monovalent ion (Na(+)) or at 10 mM divalent ion (Ca(2+)). This observation has verified the conflicting role of colloidal stability in magnetophoretic separation.

자기분리가 가능한 지르코늄 자성 흡착제의 합성과 인 흡착 특성

The purpose of this study, is to separate magnetic separation devices using permanent magnets by using magnetization characteristics remaining in treated water after adsorption and synthesizing phosphorus adsorbent capable of magnetic separation for efficient removal of phosphorus. The synthesis of the adsorbent which set Zirconium(Zr) having high friendly features for phosphorus as an element, and by synthesizing Iron Oxide(, another name of is magnetite) being able to grant magnetism to Zirconium Sulfate(), zirconium magnetic adsorbent(ZM) were manufactured. In order to consider the phosphorus adsorption characteristics of adsorbent ZM, batch adsorption experiment was performed, and based on the results, pH effect, adsorption isotherm, adsorption kinetics, and magnetic separation have been explore. As the experiment result, adsorbent ZM showed a tendency that the adsorption number was decreased rapidly at pH 13; however, it was showed a high amount of phosphorus removal in other range and it showed the highest amount of phosphorus removal in pH 6 of neutral range. In addtion, the Langmuir adsorption isotherm model is matched well, and D-R adsorption isotherm model is ranged 14.43kJ/mol indicating ion exchange mechanism. The result shown adsorption kinetics match well to the Pseudo-second-order kinetic model. The adsorbent ZM`s capablility of regenerating NaOH and , was high selectivity on the phosphorus without impacts on the other anions. The results of applying the treated water after adsorption of phosphorus to the magnetic separation device by using permanent magnets, shows that capture of the adsorbent by the magnetization filter was perfect. And they show the possibility of utilization on the phosphorus removal in water.

Automated Extraction of DNA from Blood and PCR Setup using a Tecan Freedom EVO Liquid Handler for Forensic Genetic STR Typing of Reference Samples

We have implemented and validated automated protocols for DNA extraction and PCR setup using a Tecan Freedom EVO liquid handler mounted with the Te-MagS magnetic separation device (Tecan, Männedorf, Switzerland). The protocols were validated for accredited forensic genetic work according to ISO 17025 using the Qiagen MagAttract DNA Mini M48 kit (Qiagen GmbH, Hilden, Germany) from fresh whole blood and blood from deceased individuals. The workflow was simplified by returning the DNA extracts to the original tubes minimizing the risk of misplacing samples. The tubes that originally contained the samples were washed with MilliQ water before the return of the DNA extracts. The PCR was setup in 96-well microtiter plates. The methods were validated for the kits: AmpFℓSTR Identifiler, SGM Plus and Yfiler (Applied Biosystems, Foster City, CA), GenePrint FFFL and PowerPlex Y (Promega, Madison, WI). The automated protocols allowed for extraction and addition of PCR master mix of 96 samples within 3.5h. In conclusion, we demonstrated that (1) DNA extraction with magnetic beads and (2) PCR setup for accredited, forensic genetic short tandem repeat typing can be implemented on a simple automated liquid handler leading to the reduction of manual work, and increased quality and throughput.

Research and Development of Magnetic Purification System for Used Wash Water of Drum

A high gradient magnetic separation system for purifying used wash water of drum was developed. The waste water is a mixture of various types of contaminant. The wastewater is made into floe containing ferromagnetic particles in the magnetic seeding tank. The magnetic seeded waste water is pumped into the high speed magnetic sedimentation device equipped with multiple permanent magnets. The small floe which can not be captured in the device is separated by a high gradient magnetic separation device using HTS (high temperature superconducting) bulk magnet. In the developed separation device, the ferromagnetic filters are installed in the flow channel to generate high magnetic field gradient. The combination of these devices can reduce the load to the magnetic separation system and enables long-time operation. It was found that the COD value can be currently reduced from ca. 200-500 to less than 100 ppm. It was shown that this system satisfies the requirements to be used as a magnetic separation system for the used wash water of drum.