An Overview of the Automated and On-Line Systems to Assess the Oxidative Potential of Particulate Matter

Recent years have seen a significant increase in the scientific literature related to various methods for analyzing oxidative potential (OP) of atmospheric particulate matter (PM). The presence of several types of PM, differing chemical and physical properties, released by both anthropogenic and natural sources, leads to numerous health issues in living organisms and represents an attractive target for air quality monitoring. Therefore, several studies have focused on developing rapid and self-operative tests, employing different target molecules to assess OP of atmospheric aerosols as well as unique approaches to overcome some of the most common laboratory-related issues in this kind of analysis. This work provides an overview of online and automated systems, as well as a broad picture of the state-of-art of the various devices and methods developed on this topic over the last two decades. Moreover, representative studies on this subject will be discussed, analyzing the advantages and drawbacks of the developed automated techniques

Oxidative potential of fine aerosols from a Portuguese urban-industrial area: preliminary results

Trabalho apresentado em CQ UL 5th Meeting "Forging Bonds", 12-14 julho 2022, Lisboa, PortugalN/

Oxidative potential, cytotoxicity, and intracellular oxidative stress generating capacity of PM10: a case study in South of Italy

Long and short-term exposure to atmospheric particulate matter (PM) has detrimental effects on human health. The effective mechanisms leading to PM toxicity are still not fully understood, even if it is known that physical-chemical properties, strongly influenced by sources and atmospheric processes, are known to play an important role. In this work, PM10 samples were collected, at an urban background site in southern Italy, to determine cytotoxicity (using MTT test on A549 cells), genotoxicity (using the comet assay), and intracellular oxidative stress on A549 cells exposed for 24h to aqueous extracts of PM10 samples. Organic carbon (OC) and elemental carbon (EC) content of PM10 and acellular determination of oxidative potential with DTT assay was performed with the objective to compare results of acellular and cellular biological assays. Cellular (OSGCV and MTTV) and acellular (OPDTTV) outcomes, normalised in volume, are well correlated (statistical significant results) with carbon content suggesting that combustion sources play an important role in deter-mining cellular oxidative stress and cytotoxicity of PM10. Even if the number of data is limited, genotoxicity results are well correlated (Pearsons > 0.95) with OSGCV and MTTV and a weaker, but statistically significant correlation was observed with OPDTTV. OSGCV is well correlated with the cell mortality observed with MTTV test and a lower, but still statistical significant correlation is observed between MTTV and OPDDTV. A statistically significant correlation was found between OPDTTV and OSGCV results. When the outcomes of cellular and acellular assay are compared normalised in mass (i.e. intrinsic values), the correlations become significantly weaker suggesting that the different sources acting on the site produces particulate matter with different toxicological potential influ-encing differently the biological tests studie

Correlation of Oxidative Potential with Ecotoxicological and Cytotoxicological Potential of PM10 at an Urban Background Site in Italy

: It is known that exposure to atmospheric particulate matter (PM) has detrimental effects on health. However, specific mechanisms of toxicity are still not fully understood depending on several physical and chemical properties of PM. In recent years, there has been a growing evidence that oxidative stress is an important mechanism of PM toxicity leading to the hypothesis to use acellular evaluation of oxidative potential (OP) as a global indicator of potential health effects of PM. However, when OP data are correlated with the outcomes of in vitro (or in vivo) toxicological tests, there are contrasting results. In this work an analysis of PM10 health effect indicators was done, using the acellular DTT assay to retrieve OPDTT, the Microtox® test on Vibrio fischeri bacterium to assess the ecotoxicological potential, and the in vitro MTT assay on the human cell line A549 to estimate the cytotoxicological potential. The objective was to evaluate the correlation among acellular OPDTT and the results from toxicological and ecotoxicological bioassays and how these health-related indicators are correlated with atmospheric PM10 concentrations collected at an urban background site in Southern Italy. Results indicated that both bioassays showed time-dependent and dose-dependent outcomes. Some samples presented significant ecotoxic and cytotoxic response and the correlation with PM10 concentration was limited, suggesting that these health endpoints depend on PM10 chemical composition and not only on exposure concentrations. OPDTT showed a statistically significant correlation with PM10 concentrations. MTT and Microtox outcomes were not correlated suggesting that the two toxicological indicators are sensitive to different physical-chemical properties of PM10. Intrinsic oxidative potential OPDTTM (DTT activity normalised with PM10 mass) was correlated with mortality observed with MTT test (normalized with PM10 mass), however, it was not correlated with Microtox outcome

Nickel-macrocycle interaction in nickel(II) porphyrins and porphyrazines bearing alkylthio β-substituents: A combined DFT and XPS study

An electronic structure analysis of two nickel(II) tetrapyrrole complexes bearing β-alkylthio substituents, NiOMTP and NiOETPz, has been carried out through a combination of highresolution XPS experiments and DFT calculations. The Ni 2p XPS spectra show a 0.5 eV shift to higher energy of the Ni 2p3/2 and Ni 2p1/2 binding energies on going from the porphyrin to the porphyrazine complex. This shift, which is well-reproduced by relativistic spin-orbit ZORA calculations, is indicative of a depletion of electron density on the central metal. Such a depletion of electron density is related to the macrocycle-induced changes in the metal-ligand interactions. In the porphyrazine complex both the ligand to metal σ donation and the metal to ligand π-back donation increase. The latter increases slightly more than the former, however, leading to a decrease of electron density on the central metal

Itinerario Rosa. Tavola Rotonda dal titolo:Quando la tecnologia imita la natura: anche fra macchina e corpo l’integrazione nasce dal dialogo» I progressi della biosensoristica applicata alla medicina

Tavola rotonda sponsorizzata dal Comune di Lecce, nell'ambito dell'Itinerario Rosa, manifestazione di valorizzazione della cultura ed imprenditoria al femminile e dall'Università del Salento, nell'ambito della Settimana della Cultura Scientific

Itinerario Rosa, Tavola Rotonda sul tema «Quando la tecnologia imita la natura: anche fra macchina e corpo l’integrazione nasce dal dialogo» I progressi della biosensoristica applicata alla medicina.

La manifestazione è organizzata ogni anno dal Comune di Lecce per la valorizzazione il ruolo sociale e culturale della donna. https://www.comune.lecce.it/news/2017/02/27/tutti-gli-eventi-in-programma-per-itinerario-rosa La tavola rotonda è stata inserita dalla settimana della cultura scientifica dell'Università del Salent

Oxidative Potential of Atmospheric Aerosols

The OP can be evaluated through several in vitro assays, but protocols employing chemical (acellular) assays have become common as well. Acellular assays can be useful for investigating the PM properties which are responsible for oxidative stress: ROS compounds can either be carried by components of the aerosol itself (particle-bound ROS) or induced by the catalytic activity exerted by aerosol constituents (PM-induced ROS). The recent advances in the characterization of PM oxidative potential are reported and discussed