Capturing Efficiency Research Articles

Development of IMBs-qPCR method for detection of foodborne Salmonella

Rapid and accurate detection of pathogenic microorganism is critical for food safety. Salmonella is one of the common causes of food poisoning. In the present work, polyclonal antibody against the recombinant PagN protein was prepared, and coupled with carboxylated magnetic beads to form immunomagnetic beads (IMBs) for capturing Salmonella, which was then combined with qPCR technology which used the specific primers of invA gene to accurately quantify the number of colonies, thus establishing the IMBs-qPCR method for detection of Salmonella. 0.2 mg IMBs could specifically concentrate Salmonella, with the stable capturing efficiency of 80%, corresponding to the concentrations of 102 - 105 CFU/mL. The minimum detection limit concentration was 101 CFU/mL. The method was applied for detection and enumeration of Salmonella in pork and milk samples, and the capture efficiency of 77.38 and 80.92% were obtained. In summary, the IMBs-qPCR method established herein could effectively detect Salmonella with good specificity and sensitivity. The whole detection time was less than 9 h, which laid a foundation for development of a rapid detection kit for foodborne pathogens.

Thermodynamic analysis of a sorption-enhanced gasification process of municipal solid waste, integrated with concentrated solar power and thermal energy storage systems for co-generation of power and hydrogen

A system of coupled CO2 capture and gasification has led to a new concept entitled sorption-enhanced gasification (SEG) which can increase H2 concentration in the syngas composition. This study proposed a novel configuration of the SEG system comprising concentrated solar power and thermal energy storage systems. Calcium looping (CaL) is utilized as the CO2 capture process. Unlike conventional SEG systems in which calcination heat demand is supplied by an oxy-combustion process, this study considers a heliostat field to provide heat for sorbent regeneration. The solar and thermal energy storage systems are simulated dynamically to achieve accurate results. A steam Rankine cycle is also designed to recover the released heat sources through the SEG system. The overall system performance is explored through energy and exergy analyses. Based on the results, the proposed system managed to produce 0.58 kg/s pure hydrogen in addition to 13.96 MW of net electrical power. Meanwhile, CO2 is captured from syngas composition with capturing efficiency of 95%. The energy analysis shows cold gas efficiency and the annual total energy efficiency of 87.76 and 70.74%, respectively. Based on exergy analysis results, the carbonator reactor exhibits the highest permeance compared to the gasifier and calciner reactors, with an exergy efficiency of 88.74%. Parametric study results show an increase in the cold gas efficiency, hydrogen production rate, and electrical energy efficiency with enhancing steam-to-biomass ratio. An increase in CO2 capture efficiency also improves both the electrical energy efficiency and H2 concentration of the syngas composition. CO2 capture efficiency and S/B ratio are inversely related to the exergy efficiency of the system.

Surface functionalization of microporous carbon fibers by vapor phase methods for CO2 capture

The removal of excess CO2 from the atmosphere is expected to play a major role in the mitigation of global warming. Solid-state adsorbents, consisting of CO2-binding functionalities on porous supports, can provide high CO2 capture capacities with low energy requirements. In this contribution, we report on the vapor-phase functionalization of porous carbon fibers with amine functionalities. Functionalization occurs either via direct exposure to cyclic azasilane molecules (2,2-dimethoxy-1,6-diaza-2-silacyclooctane) or by the atomic layer deposition of Al2O3 followed by exposure to azasilane. XPS analysis and SEM/energy-dispersive x-ray spectroscopy (EDX) measurements confirmed Al2O3 deposition and amine functionalization. Yet, the two different functionalization approaches led to different amine loadings and distinct differences in porosity upon functionalization, which affected CO2 capture. Combining Al2O3 and amine functionalization resulted in fast CO2 sorption with superior capturing efficiency. In contrast, direct functionalization resulted in strong reduction of the surface area of the porous support and limited gas exchange. We attribute the superior capture efficiency to the porosity level achieved when combining Al2O3 and amine functionalization demonstrating that this approach might be valuable for compact high-throughput direct air, CO2 capture systems.

Highly efficient iodine capture by hydrophobic bismuth-based chrysotile membrane from humid gas streams

Because of their non-toxicity and low cost, bismuth-based materials have received considerable attention for the capture of gaseous iodine, especially for the removal of radioactive iodine in nuclear post-processing plants. In the actual operation conditions of reprocessing plant, the presence of water vapor must be considered as an important factor because it will significantly affect the iodine capturing efficiency for most iodine-capturing materials. To address this problem, we successfully synthesized a hydrophobic bismuth-based chrysotile membrane, which was modified by the silane coupling agent KH570. The chrysotile fiber was chosen to provide rich reactive sites for bismuth loading, and the bismuth was chosen due to its high affinity to iodine. The hydrophobic surface endowed by KH570 acts as a ‘protecting layer’ when water vapor exists during iodine adsorption. The maximum of iodine capture efficiency of the prepared membrane reached 483.37 mg/g in air, and 443.04 mg/g under 75 % relative humidity. Comparing hydrophobic membrane with one that non-modified by KH570, the hydrophobic membrane increases about 54 % iodine adsorption capacity in humid condition. This study provides a certain reference value for the application of bismuth-based materials in iodine removal under humid conditions.

Microfluidic-Assisted CTC Isolation and In Situ Monitoring Using Smart Magnetic Microgels.

Capturing rare disease-associated biomarkers from body fluids can offer an early-stage diagnosis of different cancers. Circulating tumor cells (CTCs) are one of the major cancer biomarkers that provide insightful information about the cancer metastasis prognosis and disease progression. The most common clinical solutions for quantifying CTCs rely on the immunomagnetic separation of cells in whole blood. Microfluidic systems that perform magnetic particle separation have reported promising outcomes in this context, however, most of them suffer from limited efficiency due to the low magnetic force generated which is insufficient to trap cells in a defined position within microchannels. In this work, a novel method for making soft micromagnet patterns with optimized geometry and magnetic material is introduced. This technology is integrated into a bilayer microfluidic chip to localize an external magnetic field, consequently enhancing the capture efficiency (CE) of cancer cells labeled with the magnetic nano/hybrid microgels that are developed in the previous work. A combined numerical-experimental strategy is implemented to design the microfluidic device and optimize the capturing efficiency and to maximize the throughput. The proposed design enables high CE and purity of target cells and real-time time on-chip monitoring of their behavior. The strategy introduced in this paper offers a simple and low-cost yet robust opportunity for early-stage diagnosis and monitoring of cancer-associated biomarkers.

Study on vibration energy harvesting of offshore platform by energy harvester based on nonlinear energy sink

Under the impacts of waves and other marine environment, the jacket offshore platform has an obvious vibration and generates lots of energy. Meanwhile, the platform may suffer fatigue damage. The vibration energy harvesting of a jacket offshore platform under random waves with a nonlinear energy sink (NES) was investigated, and a NES-Energy harvester (NES-EH) was then designed by combining an electromagnetic linear generator with the NES. Moreover, the dynamic model of the NES-EH-offshore platform was built, and the electromagnetic damping and stiffness of the energy harvester were optimized by analyzing the energy capture efficiency and root mean square reduction of the platform displacement. The effects of NES nonlinear stiffness and damping, peak period and effective wave height of irregular waves on the capture power and width of the NES-EH were also analyzed. The results show that nonlinear stiffness and damping of the NES impact the energy capturing efficiency of the NES-EH; the smaller the damping and nonlinear stiffness, the higher the power captured by electromagnetic damping in the NES-EH. Compared with NES, the NES-EH system has a better effect on the vibration control of the platform and can better capture considerable vibration energy.

Cellulose Mediated Transferrin Nanocages for Enumeration of Circulating Tumor Cells for Head and Neck Cancer

Herein we report a hierarchically organized, water-dispersible ‘nanocage’ composed of cellulose nanocrystals (CNCs), which are magnetically powered by iron oxide (Fe3O4) nanoparticles (NPs) to capture circulating tumor cells (CTCs) in blood for head and neck cancer (HNC) patients. Capturing CTCs from peripheral blood is extremely challenging due to their low abundance and its account is clinically validated in progression-free survival of patients with HNC. Engaging multiple hydroxyl groups along the molecular backbone of CNC, we co-ordinated Fe3O4 NPs onto CNC scaffold, which was further modified by conjugation with a protein - transferrin (Tf) for targeted capture of CTCs. Owing to the presence of Fe3O4 nanoparticles, these nanocages were magnetic in nature, and CTCs could be captured under the influence of a magnetic field. Tf-CNC-based nanocages were evaluated using HNC patients’ blood sample and compared for the CTC capturing efficiency with clinically relevant Oncoviu platform. Conclusively, we observed that CNC-derived nanocages efficiently isolated CTCs from patient’s blood at 85% of cell capture efficiency to that of the standard platform. Capture efficiency was found to vary with the concentration of Tf and Fe3O4 nanoparticles immobilized onto the CNC scaffold. We envision that, Tf-CNC platform has immense connotation in ‘liquid biopsy’ for isolation and enumeration of CTCs for early detection of metastasis in cancer.

Structure and performance of electroblown PVDF‐based nanofibrous electret filters

AbstractPoly(vinylidene fluoride) (PVDF)‐based nanofibrous mats were produced via electrically assisted solution blowing (electroblowing). Morphology and filtration properties of the nanofibrous mats were investigated as a function of polymer concentration and applied voltage. The average fiber diameter was reduced from 727 ± 366 nm to 408 ± 143 nm and from 424 ± 233 nm to 328 ± 105 nm, using 16 wt% and 12 wt% concentrations, respectively, with an increase of electric voltage from 0 to 30 kV. In addition, the pore size of the mats produced from 12 wt% concentration decreases with the increase of electric voltage. Results showed that electroblown mats possess high filtration properties and performance. Enhancement of mechanical capturing efficiency is attributed to the reduction in fiber diameter and pore size. The enhancement of electrostatic capturing efficiency is thought to be from the improved electret property of the mats, which eliminates the need for a second step to polarize nanofibrous mats. As a result, both mechanical and electrostatic capture efficiency of the mats is enhanced compared to solution blown PVDF mats. The emerging electret property might be due to the accumulation of the electrostatic charges at high voltage and the enhanced polarized β phase, which is the result of the high drawing ratio applied to the polymer jet during the spinning process.

Direct Solvent-Free Modification of the Inner Wall of the Microchip for Rapid DNA Extraction with Enhanced Capturing Efficiency

Nucleic acid (NA) extraction and purification are one of the crucial steps for NA-based molecular diagnosis. However, the currently developed methods are still suffering from many issues including long process time, complicated steps, requirement of trained personnel and potential inhibition caused by chaotropic agents and/ or residual reagents. Herein, a surface-modified NA extraction microchip (SNC) is newly fabricated by introducing poly(2-dimethylaminomethyl styrene) (pDMAMS) film engaged directly on the microchip surface via initiated chemical vapor deposition (iCVD) process. The positively charged SNC inner surface could directly capture the negatively charged NA efficiently and its performance is confirmed by fluorescence microscopy and X-ray photoelectron spectroscopy. The developed SNC exhibits the deoxyribonucleic acid (DNA) capture efficiency higher than 92% regardless of initial DNA concentration in range of 20 ng/µL to 0.01 ng/µL. With this versatile DNA-capturing surface, the genomic DNAs of Escherichia Coli O157:H7 (E. coli O157:H7) is successfully extracted directly from cell lysate in the SNC with higher than 90% of efficiency within 30 min. The extraction time can be reduced to at least of 10 min maintaining extraction efficiency higher than 50%. Furthermore, the genomic DNAs are directly extracted using the SNC without loss from various real samples including juice, milk and blood serum. The proposed SNC enables us to perform an one-step NA extraction for molecular diagnosis and has the potential to be integrated into a micro-total analysis in the fields of point-of-care diagnosis.

Antibody-Functional Microsphere-Integrated Filter Chip with Inertial Microflow for Size-Immune-Capturing and Digital Detection of Circulating Tumor Cells.

Circulating tumor cells (CTCs) in blood is the direct cause of tumor metastasis. The isolation and detection of CTCs in the whole blood is very important and of clinical value in early diagnosis, postoperative review, and personalized treatment. It is difficult to separate all types of CTCs that efficiently rely on a single path due to cancer cell heterogenicity. Here, we designed a new kind of "filter chip" for the retention of CTCs with very high efficiency by integrating the effects of cell size and specific antigens on the surface of tumor cells. The filter chip consists of a semicircle arc and arrays and can separate large-scale CTC microspheres, which combined with CTCs automatically. We synthesized interfacial zinc oxide coating with nanostructure on the surface of the microsphere to increase the specific surface area to enhance the capturing efficiency of CTCs. Microspheres, trapped in the arrays, would entrap CTCs, too. The combination of the three kinds of strategies resulted in more than 90% capture efficiency of different tumor cell lines. Furthermore, it is easy to find and isolate the circulating tumor cells from the chip as tumor cells would be fixed inside the structure of a filter chip. To avoid the high background contamination when a few CTCs are surrounded by millions of nontarget cells, a digital detection method was applied to improve the detection sensitivity. The CTCs in the whole blood were specifically labeled by the antibody-DNA conjugates and detected via the DNA of the conjugates with a signal amplification. The strategy of the antibody-functional microsphere-integrated microchip for cell sorting and detection of CTCs may find broad implications that favor the fundamental cancer biology research, the precise diagnosis, and monitoring of cancer in the clinics.

Optimizing Circulating Tumor Cells' Capture Efficiency of Magnetic Nanogels by Transferrin Decoration.

Magnetic nanogels (MNGs) are designed to have all the required features for their use as highly efficient trapping materials in the challenging task of selectively capturing circulating tumor cells (CTCs) from the bloodstream. Advantageously, the discrimination of CTCs from hematological cells, which is a key factor in the capturing process, can be optimized by finely tuning the polymers used to link the targeting moiety to the MNG. We describe herein the relationship between the capturing efficiency of CTCs with overexpressed transferrin receptors and the different strategies on the polymer used as linker to decorate these MNGs with transferrin (Tf). Heterobifunctional polyethylene glycol (PEG) linkers with different molecular weights were coupled to Tf in different ratios. Optimal values over 80% CTC capture efficiency were obtained when 3 PEG linkers with a length of 8 ethylene glycol (EG) units were used, which reveals the important role of the linker in the design of a CTC-sorting system.

Magnetic CoFe 2 O 4 @ melamine based hyper-crosslinked polymer: A multivalent dendronized nanostructure for fast bacteria capturing from real samples

Polymeric compounds are main types of advanced materials to prepare antibacterial coating as well as water treatment system hence this work was aimed to prepare a polymeric nanostructure with excellent bacteria capture efficiency. Dendronized melamine – resorcinol was synthesized by a condensation reaction. To simplify polymer collection from aqueous solutions, a magnetic nanocomposite of the polymer was also prepared. For this purpose, CoFe2O4 nanoparticles were synthesized by solid-state combustion route using cellulose as fuel. Bacteria removal efficiency was studied by uptake of Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria from water, milk and fruit juice samples. Effective parameter on the capturing efficiency including; solution pH, contact time and nanocomposite dosage were optimized. Results confirmed the positive role of presented nanostructure for fast capturing of bacterial pathogens with high efficiency (more than 99%).

Glucose reinforced Fe3O4@cellulose mediated amino acid: Reusable magnetic glyconanoparticles with enhanced bacteria capture efficiency

In this study glucose reinforced Fe3O4@cellulose glyconanoparticles (MGN) were prepared using epichlorohydrin and amino acid (lysine and arginine) as a linker. Bacillus capturing capability of amino acid modified Fe3O4@cellulose was compared to the glucose reinforced system. Results showed enhanced bacterial capturing of MGN relative to amino acid modified particles. Bacterial capturing efficiencies were increased to 91% and 95% in the magnetic cellulose arginine-glucose (MCAG) and magnetic cellulose lysine-glucose (MCLG), respectively, which confirmed the role of synergism on microbial efficiency. Effective parameters on bacterial capturing efficiency including; solution pH, contact time, dosage of MGN and the presence of some anions were also investigated. Moreover, presented system was employed for bacteria capturing from river water, sea water and milk samples. The results showed that these nanocomposites have good performance to be used as reusable antimicrobial magnetic materials. The results showed that these nanocomposites have good reusability after three cycles of sorption and desorption which confirmed the efficiency of the system for bacterial removing from water solutions.

T4 bacteriophage conjugated magnetic particles for E. coli capturing: Influence of bacteriophage loading, temperature and tryptone

This work demonstrates the use of bacteriophage conjugated magnetic particles (Fe3O4) for the rapid capturing and isolation of Escherichia coli. The investigation of T4 bacteriophage adsorption to silane functionalised Fe3O4 with amine (NH2), carboxylic (COOH) and methyl (CH3) surface functional groups reveals the domination of net electrostatic and hydrophobic interactions in governing bacteriophage adsorption. The bare Fe3O4 and Fe3O4-NH2 with high T4 loading captured 3-fold more E. coli (∼70% capturing efficiency) compared to the low loading T4 on Fe3O4-COOH, suggesting the significance of T4 loading in E. coli capturing efficiency. Importantly, it is further revealed that E. coli capture is highly dependent on the incubation temperature and the presence of tryptone in the media. Effective E. coli capturing only occurs at 37°C in tryptone-containing media with the absence of either conditions resulted in poor bacteria capture. The incubation temperature dictates the capturing ability of Fe3O4/T4, whereby T4 and E. coli need to establish an irreversible binding that occurred at 37°C. The presence of tryptophan-rich tryptone in the suspending media was also critical, as shown by a 3-fold increase in E. coli capture efficiency of Fe3O4/T4 in tryptone-containing media compared to that in tryptone-free media. This highlights for the first time that successful bacteria capturing requires not only an optimum tailoring of the particle’s surface physicochemical properties for favourable bacteriophage loading, but also an in-depth understanding of how factors, such as temperature and solution chemistry influence the subsequent bacteriophage-bacteria interactions.

Capture efficiency of dynamic pH junction focusing in capillary electrophoresis.

Dynamic pH junction is one of the techniques used to overcome the issue of poor concentration sensitivity in CE. By introducing a long sample plug in the capillary and focusing the target molecules at the pH boundary between the sample plug and background electrolyte, this focusing technique can achieve a detection limit that is one to two orders of magnitude better than conventional CE. For quantification purposes, the capturing efficiency of the injected molecules should be scrutinized. Focusing of all target molecules inside the sample plug is desired to ensure good linearity across the whole dynamic range. To test the theoretical prediction with a real experiment, nicotine is used as the test molecule for two types of dynamic pH junctions. The first one is with acidic background electrolyte, and can accommodate both optical detection methods and positive-ion mode mass spectrometric detection, while the other is suitable for optical detection only due to the use of basic separation background electrolyte. With a theoretical simulation study, it is demonstrated that, for either of these dynamic pH junctions, focusing of at least 95% of target molecule injected into the capillary was easily achievable. More importantly, a longer sample plug could generate a high percentage of molecules captured by dynamic pH junction focusing. Sharp, symmetrical peaks and good linearity for calibration curve can be obtained. Real samples with complex matrixes were also used to demonstrate that nicotine can be selectively focused and quantified using CE-MS.

Gravity induced densification of floating crude oil by granular materials: Effect of particle size and surface morphology

Densification and sedimentation of floating crude oil to the bottom of water column reduces the radius of a spill and its mobility, preventing direct contamination of beaches, coastal flora and fauna. Performances of different natural granular materials were evaluated for capturing efficiency of floating fresh South Louisiana crude oil. The granular materials studied were quartz sand with medium (20–30mesh) and fine (40–100mesh) particle size, limestone with coarse (4–10mesh) and medium (16–40mesh) particle size, beach sand (20–80mesh), and clay (kaolin with ferric oxide; passing 200mesh). Beach sand (mixture of quartz and limestone 20–80mesh) and limestone (16–40mesh) demonstrated better performance for capture, densification and submergence of the crude oil among the materials evaluated. The behavior of granular particles with the hydrophobic phase can be classified as (1) immersion entrapment inside the hydrophobic phase (slurry), and (2) partial encapsulation of the hydrophobic phase by a single layer of particles (raft). With crude oil, the particles were primarily entrapped within the hydrophobic phase. Study of the effect of particle size and morphology (i.e., porosity) of the granular materials on capture performance showed that average surface pore size did not have a significant effect on aggregation with oil, however, higher capture efficiency was observed with materials of higher surface porosity (beach sand and limestone). The experiments revealed that there is a critical particle size range (passing 10mesh) which resulted in more effective aggregation of the granular materials with crude oil.

Characterization of a microfluidic magnetic bead separator for high-throughput applications

We present a novel microfluidic magnetic bead separator for high-throughput applications. The system consists of an array of small Nd–Fe–B permanent magnets arranged into a checkerboard pattern with alternating magnetization directions and an array of integrated permalloy elements encapsulated in the bottom of a microfabricated separation chamber. The permanent magnets provide magnetic forces on millimeter-scale, whereas the integrated permalloy elements enhance local forces hundredfold on ∼10μm scale near the bottom of separation chamber. The fabrication of the chip is based on a multilayer SU-8 process combined with permalloy electroplating. The bead capturing behavior in a 10μL separation chamber was demonstrated using 250nm Nanomag-D® plain silica beads. The capture efficiency of the system was quantified using vibration sample magnetometry. The experimental results show that magnetic beads can be captured with efficiencies of 91% and 54% at flow rates of 1mL/min and 4mL/min, corresponding to average linear fluid velocities of 1.7cm/s and 6.7cm/s, respectively. The integration of soft magnetic elements in the chip results in a slightly higher capturing efficiency. However, the distribution of captured beads is much more uniform in the system with soft magnetic elements than in that without soft magnetic elements. The results demonstrate that the magnetic bead separator is capable of high-throughput sample preparation, e.g., for cleaning inhibitors in DNA samples prior to PCR amplification.

Concentration of Bacillus Spores by Using Silica Magnetic Particles

Silica particles are mainly used for the concentration of nucleic acid for diagnostic purposes. This is usually done under acidic or chaotropic conditions that will demolish most of the living organisms and prevent the application of other diagnostic tests. Here we describe the development of a method for the capturing and concentration of Bacillus spores using silica magnetic particles to enable fast and sensitive detection. We have shown that capturing various Bacilli spores via silica magnetic particles is limited, with large differences between spore batches (42 +/- 25%). The hydrophobic exosporium layer of spore limits the capture by the hydrophilic silica beads. Partial removal of Bacillus exosporium increases capture efficiency. To increase capturing efficiency without harming the spores' viability, a cationic lipid, didecyldimethylammonium bromide (DDAB), was used as a coat for the negatively charged silica particles. DDAB treatment increased capture efficiency from 42% to more than 90%. Using this method, we were able to capture as few as 100 Bacillus anthracis spores/mL with 90% efficacy. Release of captured spores was achieved by the addition of albumin. The capture and release processes were verified by plating and by flow cytometry using light scatter analysis. The method is simple, efficient, easy to operate, and fast.

Adhesive tapes as capturing surfaces in Burkard sampling

Although pressure‐sensitive adhesive tapes appear to offer many advantages over traditional adhesives in sampling with a Hirst‐type spore trap, their particle capturing efficiency has never been documented. In this paper, the particle capture efficiency of four pressure‐sensitive adhesive tapes was compared to the standard vaseline adhesive in the Burkard 7‐day volumetric spore trap. The capture efficiency was assessed at flow rates of 8 and 101 min−1 over a 16 week period with each tape run alongside the standard. Image analysis was used to count and measure the surface area of individual inorganic and organic particles collected onto each tape. Approximately 230,000 individual particles were analysed, the majority of particles collected on both standard and pressure‐sensitive adhesive tapes had a surface area less than 150 μm2 (approximately diameter 14 μm). Capture efficiency was expressed as a percentage of the counts on the standard and classified by particle size and flow rate. For particles < 1000 μm2(<36 μm in diameter), the best adhesive tape captured 247.6% at 81 min−1 and 132.5% at 101 min−1. For particles > 1000 μm2, the best adhesive tape captured 86.9% at 81 min−1 and 69.8% at 101 min−1. In addition to image analysis, manual counts of pollen grains and Alternaria‐like spore were performed over a four day period for each adhesive and parallel standard at the flow rate of 101 min−1. On the adhesive tapes, pollen grains <20 μm, and pollen grains >20 μm with heavy ornamentation and/or free standing exine elements were captured best. For the best adhesive tape, the capturing efficiency compared to the standard vaseline was 83% for all pollen grains and 60% for Alternaria‐like spores.

Fibrous and Granular Filters with Electrically Enhanced Dust Capturing Efficiency

It is shown that electrification of a filter material greatly improves its capture efficiency. The electrification can be due to built-in charges (electret filter) or can be achieved by polarization in an external electric field. Various aspects of the two types of filters are discussed: design, choice of material, and filtration characteristics. In addition, the mathematical modeling of electret filters is discussed, in particular filtration with the fibers used in commercially available electret filters. Some applications of electrified filters are also briefly described (personal protection, vacuum cleaners, liquid filtration, etc.).