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Augendre L, Costa D, Escotte-Binet S, Aubert D, Villena I, Dumètre A, La Carbona S. Surrogates of foodborne and waterborne protozoan parasites: A review. Food Waterborne Parasitol 2023; 33:e00212. [PMID: 38028241 PMCID: PMC10661733 DOI: 10.1016/j.fawpar.2023.e00212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/27/2023] [Accepted: 10/27/2023] [Indexed: 12/01/2023] Open
Abstract
The protozoan parasites Cryptosporidium parvum, Cyclospora cayetanensis, and Toxoplasma gondii are major causes of waterborne and foodborne diseases worldwide. The assessment of their removal or inactivation during water treatment and food processing remains challenging, partly because research on these parasites is hindered by various economical, ethical, methodological, and biological constraints. To address public health concerns and gain new knowledge, researchers are increasingly seeking alternatives to the use of such pathogenic parasites. Over the past few decades, several non-pathogenic microorganisms and manufactured microparticles have been evaluated as potential surrogates of waterborne and foodborne protozoan parasites. Here, we review the surrogates that have been reported for C. parvum, C. cayetanensis, and T. gondii oocysts, and discuss their use and relevance to assess the transport, removal, and inactivation of these parasites in food and water matrices. Biological surrogates including non-human pathogenic Eimeria parasites, microorganisms found in water sources (anaerobic and aerobic spore-forming bacteria, algae), and non-biological surrogates (i.e. manufactured microparticles) have been identified. We emphasize that such surrogates have to be carefully selected and implemented depending on the parasite and the targeted application. Eimeria oocysts appear as promising surrogates to investigate in the future the pathogenic coccidian parasites C. cayetanensis and T. gondii that are the most challenging to work with.
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Affiliation(s)
- Laure Augendre
- EA 7510 ESCAPE Epidemiosurveillance and Circulation of Parasites in the Environment, University of Reims Champagne Ardennes, Faculty of Medicine, SFR Cap Santé Fed 4231, 51 Rue Cognacq Jay, 51096 Reims Cedex, France
- ACTALIA Food Safety, 310 Rue Popielujko, 50000, Saint-Lô, France
| | - Damien Costa
- EA 7510 ESCAPE Epidemiosurveillance and Circulation of Parasites in the Environment, University of Rouen Normandie, University Hospital of Rouen, 22 Boulevard Gambetta, 76183 Rouen Cedex, France
| | - Sandie Escotte-Binet
- EA 7510 ESCAPE Epidemiosurveillance and Circulation of Parasites in the Environment, University of Reims Champagne Ardennes, Faculty of Medicine, SFR Cap Santé Fed 4231, 51 Rue Cognacq Jay, 51096 Reims Cedex, France
| | - Dominique Aubert
- EA 7510 ESCAPE Epidemiosurveillance and Circulation of Parasites in the Environment, University of Reims Champagne Ardennes, Faculty of Medicine, SFR Cap Santé Fed 4231, 51 Rue Cognacq Jay, 51096 Reims Cedex, France
| | - Isabelle Villena
- EA 7510 ESCAPE Epidemiosurveillance and Circulation of Parasites in the Environment, University of Reims Champagne Ardennes, Faculty of Medicine, SFR Cap Santé Fed 4231, 51 Rue Cognacq Jay, 51096 Reims Cedex, France
| | - Aurélien Dumètre
- Aix-Marseille University, IRD, AP-HM, IHU Méditerranée Infection, UMR Vectors - Tropical and Mediterranean Infections, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
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Ariyadasa S, Daear W, Abeysekera G, Billington C, Fee C, Prenner E, Pang L. Evaluation of Biopolymer Materials and Synthesis Techniques to Develop a Rod-Shaped Biopolymer Surrogate for Legionella pneumophila. Polymers (Basel) 2022; 14:polym14132571. [PMID: 35808617 PMCID: PMC9269393 DOI: 10.3390/polym14132571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 06/16/2022] [Accepted: 06/21/2022] [Indexed: 11/22/2022] Open
Abstract
Biopolymer microparticles have been developed for applications that require biocompatibility and biodegradability, such as drug delivery. In this study, we assessed the production of microparticles using carnauba wax, κ-carrageenan, alginate, and poly (lactic-co-glycolic acid) (PLGA) with the aim of developing a novel, DNA-tracer-loaded, biopolymer surrogate with a size, shape, surface charge, and relative hydrophobicity similar to stationary-phase Legionella pneumophila to mimic the bacteria’s mobility and persistence in engineered water systems. We found that the type and concentration of biopolymer, reaction conditions, and synthesis methods affected the morphology, surface charge, relative hydrophobicity, and DNA tracer loading efficiency of the biopolymer microparticles produced. Carnauba wax, κ-carrageenan, and alginate (Protanal®, and low and medium viscosity) produced highly polydisperse microspheres. In contrast, PLGA and alginate-CaCO3 produced uniform microspheres and rod-shaped microparticles, respectively, with high DNA tracer loading efficiencies (PLGA 70% and alginate-CaCO3 95.2 ± 5.7%) and high reproducibilities. Their synthesis reproducibility was relatively high. The relative hydrophobicity of PLGA microspheres closely matched the cell surface hydrophobicity of L. pneumophila but not the bacterial morphology, whereas the polyelectrolyte layer-by-layer assembly was required to enhance the relative hydrophobicity of alginate-CaCO3 microparticles. Following this surface modification, alginate-CaCO3 microparticles represented the best match to L. pneumophila in size, morphology, surface charge, and relative hydrophobicity. This new biopolymer surrogate has the potential to be used as a mimic to study the mobility and persistence of L. pneumophila in water systems where the use of the pathogen is impractical and unsafe.
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Affiliation(s)
- Sujani Ariyadasa
- Institute of Environmental Science and Research, P.O. Box 29181, Christchurch 8540, New Zealand; (G.A.); (C.B.); (L.P.)
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8041, New Zealand
- Correspondence: ; Tel.: +64-3351-6019
| | - Weiam Daear
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (W.D.); (E.P.)
| | - Gayan Abeysekera
- Institute of Environmental Science and Research, P.O. Box 29181, Christchurch 8540, New Zealand; (G.A.); (C.B.); (L.P.)
| | - Craig Billington
- Institute of Environmental Science and Research, P.O. Box 29181, Christchurch 8540, New Zealand; (G.A.); (C.B.); (L.P.)
| | - Conan Fee
- School of Product Design, University of Canterbury, Private Bag 4800, Christchurch 8041, New Zealand;
- Biomolecular Interaction Centre, University of Canterbury, Private Bag 4800, Christchurch 8041, New Zealand
| | - Elmar Prenner
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (W.D.); (E.P.)
| | - Liping Pang
- Institute of Environmental Science and Research, P.O. Box 29181, Christchurch 8540, New Zealand; (G.A.); (C.B.); (L.P.)
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King WE, Bowlin GL. Mechanical characterization and neutrophil NETs response of a novel hybrid geometry polydioxanone near-field electrospun scaffold. Biomed Mater 2021; 16. [PMID: 34404034 DOI: 10.1088/1748-605x/ac1e43] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/17/2021] [Indexed: 11/11/2022]
Abstract
Near-field electrospinning (NFES) is a direct fiber writing sub-technique derived from traditional electrospinning (TES) by reducing the air gap distance to the magnitude of millimeters. In this paper, we demonstrate a NFES device designed from a commercial 3D printer to semi-stably write polydioxanone (PDO) microfibers. The print head was then programmed to translate in a stacking grid pattern, which resulted in a scaffold with highly aligned grid fibers that were intercalated with low density, random fibers. As the switching process can be considered random, increasing the grid size results in both a lower density of fibers in the center of each grid cell as well as a lower density of 'rebar-like' stacked fibers. These scaffolds resulted in tailorable as well as greater surface pore sizes as given by scanning electron micrographs and 3D permeability as indicated by fluorescent microsphere filtration compared to TES scaffolds of the same fiber diameter. Furthermore, ultimate tensile strength, percent elongation, yield stress, yield elongation, and Young's modulus were all tailorable compared to the static TES scaffold characterization. Lastly, the innate immune response of neutrophil extracellular traps was attenuated on NFES scaffolds compared to TES scaffolds. These results suggest that this novel NFES scaffold architecture of PDO can be highly tailored as a function of programming for a variety of biomedical and tissue engineering applications.
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Affiliation(s)
- William E King
- Department of Biomedical Engineering, University of Memphis, Memphis, TN 38152, United States of America.,Department of Biomedical Engineering, University of Tennessee Health Science Center, Memphis, TN 38163, United States of America
| | - Gary L Bowlin
- Department of Biomedical Engineering, University of Memphis, Memphis, TN 38152, United States of America
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Ilyas S, Ullah NK, Ilyas M, Wennhold K, Iqbal M, Schlößer HA, Hussain MS, Mathur S. Mediating the Fate of Cancer Cell Uptake: Dual-Targeted Magnetic Nanovectors with Biotin and Folate Surface Ligands. ACS Biomater Sci Eng 2020; 6:6138-6147. [DOI: 10.1021/acsbiomaterials.0c00771] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Shaista Ilyas
- Institute of Inorganic Chemistry, University of Cologne, Greinstraße 6, 50939 Cologne, Germany
| | - Nighat K. Ullah
- Institute of Inorganic Chemistry, University of Cologne, Greinstraße 6, 50939 Cologne, Germany
| | - Muhammad Ilyas
- Professorship for Population Genetics, Department of Life Science Systems, Technical University of Munich, Liesel-Beckmann Straße 2, 85354 Freising, Germany
| | - Kerstin Wennhold
- Center for Molecular Medicine Cologne and Translational Immunology, University Hospital Cologne, 50931 Cologne, Germany
- Medical Microbiology, Immunology and Hygiene, University Hospital Cologne, Goldenfelsstraße 19-21, 50935 Cologne, Germany
| | - Maria Iqbal
- Institute of Biochemistry I, Center for Molecular Medicine, University of Cologne, Joseph-Stelzmann-Straße 52, 50931 Cologne, Germany
- Cologne Center for Genomics (CCG), University of Cologne, Weyertal 115b, 50931 Cologne, Germany
| | - Hans A. Schlößer
- Center for Molecular Medicine Cologne and Translational Immunology, University Hospital Cologne, 50931 Cologne, Germany
- Medical Microbiology, Immunology and Hygiene, University Hospital Cologne, Goldenfelsstraße 19-21, 50935 Cologne, Germany
| | - Muhammad S. Hussain
- Institute of Biochemistry I, Center for Molecular Medicine, University of Cologne, Joseph-Stelzmann-Straße 52, 50931 Cologne, Germany
- Cologne Center for Genomics (CCG), University of Cologne, Weyertal 115b, 50931 Cologne, Germany
| | - Sanjay Mathur
- Institute of Inorganic Chemistry, University of Cologne, Greinstraße 6, 50939 Cologne, Germany
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Liu L, Wang Y, Narain R, Liu Y. Functionalized polystyrene microspheres as Cryptosporidium surrogates. Colloids Surf B Biointerfaces 2019; 175:680-687. [PMID: 30590329 DOI: 10.1016/j.colsurfb.2018.12.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 12/04/2018] [Accepted: 12/17/2018] [Indexed: 11/16/2022]
Abstract
Cryptosporidium, a waterborne protozoan pathogen that can cause gastrointestinal illness, is often found in surface waters that are used to supply drinking water. Filtration is a major process to remove Cryptosporidium in drinking water treatment. However, interactions between oocysts and filter media are still unclear and no satisfactory surrogates have been identified for quantifying their filtration removal in porous media. In the present study, polystyrene microsphere with a size, density, and shape similar to Cryptosporidium was modified with glycoprotein or synthesized biomolecules to mimic the surface properties of live Cryptosporidium oocyst. Deposition kinetics between live Cryptosporidium/modified microspheres and filter media were studied at the molecular scale using a quartz crystal microbalance with dissipation monitoring (QCM-D) and at the laboratory-scale using sand-packed columns. Both QCM-D and column experiments underlined the importance of Cryptosporidium surface charge and hydrophobicity on their attenuation and transport in porous media. As compared to live Cryptosporidium, glycopolymer and zwitterionic polymer co- odified polystyrene microspheres (later called copolymers-modified microspheres) represent comparable surface properties, adsorption kinetics on filter surfaces, and transport and deposition behaviors in filter columns; hence were selected as appropriate Cryptosporidium surrogates. This study improves our understanding on how surface characteristics impact Cryptosporidium transport behaviors in porous media and contributes to our capacity to evaluate the attenuation of Cryptosporidium in natural and engineered aquatic environments.
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Affiliation(s)
- Lu Liu
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 2R3, Canada; Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 2R3, Canada
| | - Yinan Wang
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 2R3, Canada; Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 2R3, Canada
| | - Ravin Narain
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 2R3, Canada.
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, T6G 2R3, Canada.
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Monis P, Lau M, Harris M, Cook D, Drikas M. Risk-based management of drinking water safety in Australia: Implementation of health based targets to determine water treatment requirements and identification of pathogen surrogates for validation of conventional filtration. Food Waterborne Parasitol 2017; 8-9:64-74. [PMID: 32095641 PMCID: PMC7034041 DOI: 10.1016/j.fawpar.2017.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/18/2017] [Accepted: 08/21/2017] [Indexed: 11/17/2022] Open
Abstract
The safety of drinking water in Australia is ensured using a risk management framework embedded within the Australian Drinking Water Guidelines (ADWG). This framework includes elements for hazard identification, risk assessment, risk mitigation, verification of barrier performance and monitoring for any changes to the hazards that influence source water quality. The next revision of the ADWG will incorporate Health-Based Targets (HBTs) for achieving microbiologically safe drinking water. This incorporates Quantitative Microbial Risk Assessment and the metric of Disability Adjusted Life Year (DALY) to define safety, with a target of 1 × 10− 6 Disability Adjusted Life Year (1 microDALY) set as the maximum tolerable disease burden from drinking water, which in the case of Cryptosporidium is < 1.3 × 10− 5 oocysts/L. The resulting product water specification, in combination with knowledge of pathogen challenges in source waters, allows the determination of the treatment requirements to ensure public safety. The ADWG revision provides default removal values for Cryptosporidium for particular treatment processes, such as conventional coagulation and dual media filtration. However, these values are based on assumptions regarding treatment plant design, operation and water quality. To properly manage risk and demonstrate compliance with the guidelines, water utilities may need to validate treatment performance for Cryptosporidium removal. A particular limitation is the absence of Cryptosporidium surrogates for full-scale filter validation. This paper will provide an overview of risk-based management of drinking water safety in Australia, the development of health-based targets for microbial pathogens and the evaluation of Cryptosporidium surrogates for conventional coagulation and dual media filtration. Used pilot-scale coagulation, sedimentation, granular media filter water treatment Compared the removals of Cryptosporidium oocysts and surrogates Pilot-scale treated water quality was comparable to full-scale treatment. Modified microspheres most similar to oocyst filtration removal Clostridium spores, algae and turbidity conservative indicators of oocyst removal Turbidity, algae have great potential as on-line indicators for oocyst removal.
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Affiliation(s)
- Paul Monis
- Australian Water Quality Centre, South Australian Water Corporation, GPO Box 1751, Adelaide, SA 5001, Australia
| | - Melody Lau
- Australian Water Quality Centre, South Australian Water Corporation, GPO Box 1751, Adelaide, SA 5001, Australia
| | - Martin Harris
- Australian Water Quality Centre, South Australian Water Corporation, GPO Box 1751, Adelaide, SA 5001, Australia
| | - David Cook
- Australian Water Quality Centre, South Australian Water Corporation, GPO Box 1751, Adelaide, SA 5001, Australia
| | - Mary Drikas
- Australian Water Quality Centre, South Australian Water Corporation, GPO Box 1751, Adelaide, SA 5001, Australia
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Sivakumaran M, Platt M. Tunable resistive pulse sensing: potential applications in nanomedicine. Nanomedicine (Lond) 2016; 11:2197-214. [PMID: 27480794 DOI: 10.2217/nnm-2016-0097] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
An accurate characterization of nanomaterials used in clinical diagnosis and therapeutics is of paramount importance to realize the full potential of nanotechnology in medicine and to avoid unexpected and potentially harmful toxic effects due to these materials. A number of technical modalities are currently in use to study the physical, chemical and biological properties of nanomaterials but they all have advantages and disadvantages. In this review, we discuss the potential of a relative newcomer, tunable resistive pulse sensing, for the characterization of nanomaterials and its applications in nanodiagnostics.
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Affiliation(s)
| | - Mark Platt
- Department of Chemistry, Loughborough University, Loughborough, LE11 3TU, UK
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Headd B, Bradford SA. Use of aerobic spores as a surrogate for cryptosporidium oocysts in drinking water supplies. WATER RESEARCH 2016; 90:185-202. [PMID: 26734779 DOI: 10.1016/j.watres.2015.12.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 12/10/2015] [Accepted: 12/13/2015] [Indexed: 05/06/2023]
Abstract
Waterborne illnesses are a growing concern among health and regulatory agencies worldwide. The United States Environmental Protection Agency has established several rules to combat the contamination of water supplies by cryptosporidium oocysts, however, the detection and study of cryptosporidium oocysts is hampered by methodological and financial constraints. As a result, numerous surrogates for cryptosporidium oocysts have been proposed by the scientific community and efforts are underway to evaluate many of the proposed surrogates. The purpose of this review is to evaluate the suitability of aerobic bacterial spores to serve as a surrogate for cryptosporidium oocysts in identifying contaminated drinking waters. To accomplish this we present a comparison of the biology and life cycles of aerobic spores and oocysts and compare their physical properties. An analysis of their surface properties is presented along with a review of the literature in regards to the transport, survival, and prevalence of aerobic spores and oocysts in the saturated subsurface environment. Aerobic spores and oocysts share many commonalities with regard to biology and survivability, and the environmental prevalence and ease of detection make aerobic spores a promising surrogate for cryptosporidium oocysts in surface and groundwater. However, the long-term transport and release of aerobic spores still needs to be further studied, and compared with available oocyst information. In addition, the surface properties and environmental interactions of spores are known to be highly dependent on the spore taxa and purification procedures, and additional research is needed to address these issues in the context of transport.
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Affiliation(s)
- Brendan Headd
- U.S. Salinity Lab USDA, ARS, 450 W. Big Springs Road, Riverside, CA 92507-4617, USA
| | - Scott A Bradford
- U.S. Salinity Lab USDA, ARS, 450 W. Big Springs Road, Riverside, CA 92507-4617, USA.
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Biotin- and Glycoprotein-Coated Microspheres as Surrogates for Studying Filtration Removal of Cryptosporidium parvum in a Granular Limestone Aquifer Medium. Appl Environ Microbiol 2015; 81:4277-83. [PMID: 25888174 DOI: 10.1128/aem.00885-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 04/10/2015] [Indexed: 11/20/2022] Open
Abstract
Members of the genus Cryptosporidium are waterborne protozoa of great health concern. Many studies have attempted to find appropriate surrogates for assessing Cryptosporidium filtration removal in porous media. In this study, we evaluated the filtration of Cryptosporidium parvum in granular limestone medium by the use of biotin- and glycoprotein-coated carboxylated polystyrene microspheres (CPMs) as surrogates. Column experiments were carried out with core material taken from a managed aquifer recharge site in Adelaide, Australia. For the experiments with injection of a single type of particle, we observed the total removal of the oocysts and glycoprotein-coated CPMs, a 4.6- to 6.3-log10 reduction of biotin-coated CPMs, and a 2.6-log10 reduction of unmodified CPMs. When two different types of particles were simultaneously injected, glycoprotein-coated CPMs showed a 5.3-log10 reduction, while the uncoated CPMs displayed a 3.7-log10 reduction, probably due to particle-particle interactions. Our results confirm that glycoprotein-coated CPMs are the most accurate surrogates for C. parvum; biotin-coated CPMs are slightly more conservative, while unmodified CPMs are markedly overly conservative for predicting C. parvum removal in granular limestone medium. The total removal of C. parvum observed in our study suggests that granular limestone medium is very effective for the filtration removal of C. parvum and could potentially be used for the pretreatment of drinking water and aquifer storage recovery of recycled water.
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Abstract
This Review focusses on the recent surge in applied research using tunable resistive pulse sensing, a technique used to analyse submicron colloids in aqueous solutions on a particle-by-particle basis.
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Affiliation(s)
- Eva Weatherall
- The MacDiarmid Institute for Advanced Materials and Nanotechnology
- School of Chemical and Physical Sciences
- Victoria University of Wellington
- New Zealand
- Callaghan Innovation
| | - Geoff R. Willmott
- The MacDiarmid Institute for Advanced Materials and Nanotechnology
- School of Chemical and Physical Sciences
- Victoria University of Wellington
- New Zealand
- The Departments of Physics and Chemistry
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Willmott GR, Fisk MG, Eldridge J. Magnetic microbead transport during resistive pulse sensing. BIOMICROFLUIDICS 2013; 7:64106. [PMID: 24396540 PMCID: PMC3855170 DOI: 10.1063/1.4833075] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 11/11/2013] [Indexed: 05/24/2023]
Abstract
Tunable resistive pulse sensing (TRPS) experiments have been used to quantitatively study the motion of 1 μm superparamagnetic beads in a variable magnetic field. Closed-form theory has been developed to interpret the experiments, incorporating six particle transport mechanisms which depend on particle position in and near a conical pore. For our experiments, calculations indicate that pressure-driven flow dominates electrophoresis and magnetism by a factor of ∼100 in the narrowest part of the pore, but that magnetic force should dominate further than ∼1 mm from the membrane. As expected, the observed resistive pulse rate falls as the magnet is moved closer to the pore, while the increase in pulse duration suggests that trajectories in the half space adjacent to the pore opening are important. Aggregation was not observed, consistent with the high hydrodynamic shear near the pore constriction and the high magnetization of aggregates. The theoretical approach is also used to calculate the relative importance of transport mechanisms over a range of geometries and experimental conditions extending well beyond our own experiments. TRPS is emerging as a versatile form of resistive pulse sensing, while magnetic beads are widely used in biotechnology and sensing applications.
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Affiliation(s)
- Geoff R Willmott
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, Wellington, New Zealand ; Callaghan Innovation, 69 Gracefield Rd., Lower Hutt, New Zealand
| | - Matthew G Fisk
- Callaghan Innovation, 69 Gracefield Rd., Lower Hutt, New Zealand ; School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - James Eldridge
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, Wellington, New Zealand ; Callaghan Innovation, 69 Gracefield Rd., Lower Hutt, New Zealand ; School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
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