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Shin HJ, Yang I, Park SR, Lee JY. Use of a sample injection loop for an accurate measurement of particle number concentration by flow cytometry. Anal Bioanal Chem 2024:10.1007/s00216-024-05387-6. [PMID: 38926227 DOI: 10.1007/s00216-024-05387-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/30/2024] [Accepted: 06/03/2024] [Indexed: 06/28/2024]
Abstract
Flow cytometry plays a pivotal role in biotechnology by providing quantitative measurements for a wide range of applications. Nonetheless, achieving precise particle quantification, particularly without relying on counting beads, remains a challenge. In this study, we introduce a novel exhaustive counting method featuring a sample loop-based injection system that delivers a defined sample volume to a detection system to enhance quantification in flow cytometry. We systematically assess the performance characteristics of this system with micron-sized polystyrene beads, addressing issues related to sample introduction, adsorption, and volume measurement. Results underscore the excellent analytical performance of the proposed method, characterized by high linearity and repeatability. We compare our approach to counting bead-based measurements, and while an approximate bias value was observed, the measured values were found to be similar between the methods, demonstrating its comparability and reliability. This method holds great promise for improving the accuracy and precision of particle quantification in flow cytometry, with implications for various fields including healthcare and environmental monitoring.
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Affiliation(s)
- Hye Ji Shin
- Biometrology Group, Division of Biomedical Metrology, Korea Research Institute of Standards and Science, 267 Gajeong-Ro, Yuseong-Gu, Daejeon, 34113, Republic of Korea
- Graduate School of Analytical Science and Technology, Chungnam National University, 99 Daehak-Ro, Yuseong-Gu, Daejeon, 34134, Republic of Korea
| | - Inchul Yang
- Biometrology Group, Division of Biomedical Metrology, Korea Research Institute of Standards and Science, 267 Gajeong-Ro, Yuseong-Gu, Daejeon, 34113, Republic of Korea
| | - Sang-Ryoul Park
- Biometrology Group, Division of Biomedical Metrology, Korea Research Institute of Standards and Science, 267 Gajeong-Ro, Yuseong-Gu, Daejeon, 34113, Republic of Korea.
| | - Ji Youn Lee
- Biometrology Group, Division of Biomedical Metrology, Korea Research Institute of Standards and Science, 267 Gajeong-Ro, Yuseong-Gu, Daejeon, 34113, Republic of Korea.
- Graduate School of Analytical Science and Technology, Chungnam National University, 99 Daehak-Ro, Yuseong-Gu, Daejeon, 34134, Republic of Korea.
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Masseroni A, Fossati M, Ponti J, Schirinzi G, Becchi A, Saliu F, Soler V, Collini M, Della Torre C, Villa S. Sublethal effects induced by different plastic nano-sized particles in Daphnia magna at environmentally relevant concentrations. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 343:123107. [PMID: 38070641 DOI: 10.1016/j.envpol.2023.123107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/14/2023] [Accepted: 12/04/2023] [Indexed: 12/19/2023]
Abstract
A growing number of studies have reported the toxic effects of nanoplastics (NPs) on organisms. However, the focus of these studies has almost exclusively been on the use of polystyrene (PS) nanospheres. Herein, we aim to evaluate the sublethal effects on Daphnia magna juveniles of three different NP polymers: PS-NPs with an average size of 200 nm, polyethylene [PE] NPs and polyvinyl chloride [PVC] NPs with a size distribution between 50 and 350 nm and a comparable mean size. For each polymer, five environmentally relevant concentrations were tested (from 2.5 to 250 μg/L) for an exposure time of 48 h. NP effects were assessed at the biochemical level by investigating the amount of reactive oxygen species (ROS) and the activity of the antioxidant enzyme catalase (CAT) and at the behavioral level by evaluating the swimming behavior (distance moved). Our results highlight that exposure to PVC-NPs can have sublethal effects on Daphnia magna at the biochemical and behavioral levels. The potential role of particle size on the measured effects cannot be excluded as PVC and PE showed a wider size range distribution than PS, with particles displaying sizes from 50 to 350 nm. However, we infer that the chemical structure of PVC, which differs from that of PE of the same range size, concurs to explain the observed effects. Consequently, as PS seems not to be the most hazardous polymer, we suggest that the use of data on PS toxicity alone can lead to an underestimation of NP hazards.
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Affiliation(s)
- Andrea Masseroni
- Department of Earth and Environmental Sciences, DISAT, University of Milano-Bicocca, Piazza Della Scienza 1, 20126, Milan, Italy
| | - Marco Fossati
- Department of Biosciences, University of Milan, Via Giovanni Celoria 26, 20133, Milan, Italy
| | - Jessica Ponti
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | | | - Alessandro Becchi
- Department of Earth and Environmental Sciences, DISAT, University of Milano-Bicocca, Piazza Della Scienza 1, 20126, Milan, Italy
| | - Francesco Saliu
- Department of Earth and Environmental Sciences, DISAT, University of Milano-Bicocca, Piazza Della Scienza 1, 20126, Milan, Italy
| | - Valentina Soler
- Department of Earth and Environmental Sciences, DISAT, University of Milano-Bicocca, Piazza Della Scienza 1, 20126, Milan, Italy
| | - Maddalena Collini
- Department of Physics "Giuseppe Occhialini, " University of Milano-Bicocca, Piazza Della Scienza 3, 20126, Milan, Italy
| | - Camilla Della Torre
- Department of Biosciences, University of Milan, Via Giovanni Celoria 26, 20133, Milan, Italy
| | - Sara Villa
- Department of Earth and Environmental Sciences, DISAT, University of Milano-Bicocca, Piazza Della Scienza 1, 20126, Milan, Italy.
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Yalamanchili J, Hennigan CJ, Reed BE. Measurement artifacts in the dithiothreitol (DTT) oxidative potential assay caused by interactions between aqueous metals and phosphate buffer. JOURNAL OF HAZARDOUS MATERIALS 2023; 456:131693. [PMID: 37245366 DOI: 10.1016/j.jhazmat.2023.131693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/15/2023] [Accepted: 05/22/2023] [Indexed: 05/30/2023]
Abstract
Metals in particulate matter (PM) are hypothesized to have enhanced toxicity based on their ability to catalyze reactive oxygen species (ROS) formation. Acellular assays are used to measure the oxidative potential (OP) of PM and its individual components. Many OP assays, including the dithiothreitol (DTT) assay, use a phosphate buffer matrix to simulate biological conditions (pH 7.4 and 37 °C). Prior work from our group observed transition metal precipitation in the DTT assay, consistent with thermodynamic equilibria. In this study, we characterized the effects of metal precipitation on OP measured by the DTT assay. Metal precipitation was affected by aqueous metal concentrations, ionic strength, and phosphate concentrations in ambient PM sampled in Baltimore, MD and a standard PM sample (NIST SRM-1648a, Urban Particulate Matter). Critically, differences in metal precipitation induced differing OP responses of the DTT assay as a function of phosphate concentration in all PM samples analyzed. These results indicate that comparison of DTT assay results obtained at differing phosphate buffer concentrations is highly problematic. Further, these results have implications for other chemical and biological assays that use phosphate buffer for pH control and their use to infer PM toxicity.
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Affiliation(s)
- Jayashree Yalamanchili
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Christopher J Hennigan
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
| | - Brian E Reed
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
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