Ascorbate assay as a measure of oxidative potential for ambient particles: Evidence for the importance of cell-free surrogate lung fluid composition

Pietrogrande, Maria Chiara; Bertoli, Ilaria; Manarini, Francesco; Russo, Mara

doi:10.1016/j.atmosenv.2019.05.012

Cited by 38 publications

(35 citation statements)

References 53 publications

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“…This explanation is also consistent with the positive correlation observed for PM samples in Milan between OP DTT m with global radiation and, to a lesser and low extent, also with T, O 3 , and chemical components formed by photochemical reactions (SO 4 2− and oxalic acid) [28]. Figure 3b, [18,24,30]). The highest OP AA V responses were measured in Bologna, as their value was nearly triple (0.75 ± 0.2 nmol min −1 m −3 ) compared to Lecce (~0.20 nmol min −1 m −3 ) with a clear increase during cold season at both sites.…”

Section: Op Responses Of Pm 10 Particlessupporting

confidence: 87%

“…In general, organic carbon (OC) and elemental carbon (EC) concentrations were quantified using a thermo-optical analyser (Sunset Laboratory OC/EC analysers) [18,30], and water-soluble organic carbon (WSOC) was analyzed with a total carbon analyzer instrument [23]. From these values, the contribution of prima (POC) and secondary organic species (SOC) to OC was estimated [24,34].…”

Section: Analytical Methodologies For Chemical Characterizationmentioning

confidence: 99%

“…Modified AA procedures have also been used, performed in a synthetic surrogate respiratory tract lining fluid (RTLF), containing endogenous antioxidants at physiological levels, which is more indicative of realistic lung conditions, i.e., reduced glutathione (GSH), uric acid (UA), and citrate (Cit), in addition to ascorbate (Asc) [30]. In some OP protocols, the remaining concentrations of antioxidants in SLF is quantified at specific time intervals, using reversed-phase HPLC with electrochemical detection and/or enzyme-linked assay for total glutathione and GSH [17,19,31,32].…”

Section: Aa and Gsh Assaysmentioning

confidence: 99%

“…Oxidative properties of fine particles were investigated at an urban site (Bologna, 400,000 inhabitants) and a rural location (SPC, san Pietro Capofiume, 30 km far from Bologna) located in the Emilia Romagna region, in the Eastern side of Po Valley, one of the most polluted areas in Europe. One monitoring campaign was conducted in February-July 2013 [18] and the other one in March 2018 [30]. OP of PM 2.5 samples in some Italian cities were also measured as a part of more general studies concerning different locations over Europe.…”

Section: Study Overviewmentioning

confidence: 99%

“…Three studies measured OP AA values of PM 2.5 samples collected at Bologna and Lecce in different seasons (data summarized in Figure 3b, [18,24,30]). The highest OP AA V responses were measured in Bologna, as their value was nearly triple (0.75 ± 0.2 nmol min −1 m −3 ) compared to Lecce (~0.20 nmol min −1 m −3 ) with a clear increase during cold season at both sites.…”

Section: Op Responses Of Pm 10 Particlesmentioning

confidence: 99%

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Review of PM Oxidative Potential Measured with Acellular Assays in Urban and Rural Sites across Italy

2019

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This work is an overview of the oxidative potential (OP) values up to date measured in Italy, with the aim to provide a picture of the spatial and seasonal variability of OP in the various geographical areas across Italy. The summarized works used the common acellular assays-based dithiothreitol (OP DTT ), ascorbic acid (OP AA ), glutathione (OP GSH ), and 2 ,7 -dichlorodfluorescein (OP DCFH ) assays. The paper describes the association of OP responses with PM chemical composition, the sensitivity of various acellular OP assays to PM components and emission sources, and PM size distribution of the measured OP values. Our synthesis indicates that crustal and transition metals (e.g., Fe, Ni, Cu, Cr, Mn, Zn, and V), secondary ions and carbonaceous components (elemental carbon, EC, organic carbon, OC and water soluble carbon, WSOC) show significant correlations with OP across different urban and rural areas and size ranges. These chemical species are mainly associated with various PM sources, including residual/fuel oil combustion, traffic emissions, and secondary organic aerosol formation. Although the OP assays are sensitive to the same redox-active species, they differ in the association with PM chemical components. The DDT assay is mainly sensitive to the organic compounds that are mostly accumulated in the fine PM fraction, i.e., tracers of burning sources, and redox active organics associated with other markers of photochemical aging. In contrast, OP AA and OP GSH were mostly responsive to metals, mainly those related to non-exhaust traffic emissions (Cu, Zn, Cr, Fe, Ni, Mn, Sn, Cd, Pb), that are mainly accumulated in the coarse PM. Among the investigated sites, our synthesis shows larger OP values in Trentino region and the Po Valley, that may be explained by the high density of anthropogenic sources, and the orographic and meteorological characteristics, that favor the pollutants accumulation and aerosol photo-oxidative aging. ). The acellular version of the 2 ,7 -dichlorodfluorescein (DCFH) assay uses the enzymatic production of the fluorescent probe largely used for the evaluation of oxidative stress in living cells.The present work summarizes the PM oxidative properties up to date measured in Italy using OP acellular assays, with the aim of giving a general insight of PM OP across the Italian territory, that has not been reported yet, in spite of the increasing number of OP measurements carried out in Europe [6,[19][20][21][22]. In addition, the study reviews the association described in previous studies between OP from different assays with several inorganic ad organic components, that effect PM oxidative properties, i.e., metals, ions, and carbonaceous components. The aim is to give a picture of the spatial and seasonal variability of different contributions to OP in the various geographical areas across Italy. The relevance of such an investigation is based on the large variability in the chemical composition of different PM size fractions in various locations across Italy, as a consequence of the stron...

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Section: Op Responses Of Pm 10 Particlessupporting

confidence: 87%

Section: Analytical Methodologies For Chemical Characterizationmentioning

confidence: 99%

Section: Aa and Gsh Assaysmentioning

confidence: 99%

Section: Study Overviewmentioning

confidence: 99%

Section: Op Responses Of Pm 10 Particlesmentioning

confidence: 99%

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Review of PM Oxidative Potential Measured with Acellular Assays in Urban and Rural Sites across Italy

2019

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Convolutional neural network prediction of molecular properties for aerosol chemistry and health effects

et al. 2022

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Quinones are chemical compounds commonly found in air particulate matter (PM).Their redox activity can generate reactive oxygen species (ROS) and contribute to the oxidative potential (OP) of PM leading to adverse health effects of aerosols. The quinones' OP and ability to form ROS are linked to their reduction potential (RP, measured in volts), a metric for the tendency to lose electrons in redox reactions. Here, we use convolutional neural networks (CNN) as quantitative structure-activity relationship (QSAR) models to relate the one-electron RP of quinones to their molecular structure. For CNN training and testing, a data set of more than 100,000 quinones with associated RP values derived from density functional theory calculations was encoded in simplified molecular input line entry system (SMILES). The best performing CNN model achieved a root mean square error (RMSE) of 0.115 V for an independent test data set and outperformed linear regression models fitted on common molecular descriptors (≥ 0.140 V RMSE). Augmentation methods were newly adapted or applied to support CNN training with smaller data sets, improving RMSE by up to approximately 37% for a data set of 321 molecules. Adjusted for solvent effects, the CNN-derived RP predictions showed good agreement with experimental data.Using the newly developed method, we identified a subset of atmospherically relevant quinones that are likely to have a high OP and play a role in aerosol health effects, which remains to be further elucidated by experimental studies. We suggest to use the presented machine learning approach in further investigations of atmospheric aerosol chemistry and health effects as well as other studies that require a target-oriented screening of the properties and effects of large classes of substances.

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Effect of filter extraction solvents on the measurement of the oxidative potential of airborne PM2.5

Pietrogrande

Bacco

Trentini

et al. 2021

Environ Sci Pollut Res

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Solvent extraction of PM2.5 samples collected on the filter is a preliminary step for assessing the PM2.5 oxidative potential (OP) using cell-free assays, as the dithiothreitol (DTT) and the ascorbic acid (AA) assays. In this study, we evaluated the effect of the solvent choice by extracting ambient PM2.5 samples with different solvents: methanol, as organic solvent, and two aqueous buffers, i.e., phosphate buffer (PB) and Gamble’s solution (G), as a lung fluid surrogate solution. Both the measured volume-based OPVDTT and OPVAA responses varied for the different extraction methods, since methanol extraction generated the lowest values and phosphate buffer the highest. Although all the tested solvents produced intercorrelated OPVDTT values, the phosphate buffer resulted the most useful for OPDTT assessment, as it provided the most sensible measure (nearly double values) compared with other extractions. The association of the measured OPV values with PM chemical composition suggested that oxidative properties of the investigated PM2.5 samples depend on both transition metals and quinones, as also supported by additional experimental measurements on standard solutions of redox-active species.

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Ascorbate assay as a measure of oxidative potential for ambient particles: Evidence for the importance of cell-free surrogate lung fluid composition

Cited by 38 publications

References 53 publications

Review of PM Oxidative Potential Measured with Acellular Assays in Urban and Rural Sites across Italy

Review of PM Oxidative Potential Measured with Acellular Assays in Urban and Rural Sites across Italy

Convolutional neural network prediction of molecular properties for aerosol chemistry and health effects

Effect of filter extraction solvents on the measurement of the oxidative potential of airborne PM2.5

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