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Pavan C, Escolano-Casado G, Bellomo C, Cananà S, Tomatis M, Leinardi R, Mino L, Turci F. Nearly free silanols drive the interaction of crystalline silica polymorphs with membranes: Implications for mineral toxicity. Front Chem 2023; 10:1092221. [PMID: 36726450 PMCID: PMC9884702 DOI: 10.3389/fchem.2022.1092221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/30/2022] [Indexed: 01/18/2023] Open
Abstract
Crystalline silica (CS) is a well-known hazardous material that causes severe diseases including silicosis, lung cancer, and autoimmune diseases. However, the hazard associated to crystalline silica is extremely variable and depends on some specific characteristics, including crystal structure and surface chemistry. The crystalline silica polymorphs share the SiO2 stoichiometry and differentiate for crystal structure. The different crystal lattices in turn expose differently ordered hydroxyl groups at the crystal surface, i.e., the silanols. The nearly free silanols (NFS), a specific population of weakly interacting silanols, have been recently advanced as the key surface feature that governs recognition mechanisms between quartz and cell membrane, initiating toxicity. We showed here that the nearly free silanols occur on the other crystalline silica polymorphs and take part in the molecular interactions with biomembranes. A set of crystalline silica polymorphs, including quartz, cristobalite, tridymite, coesite, and stishovite, was physico-chemically characterized and the membranolytic activity was assessed using red blood cells as model membranes. Infrared spectroscopy in highly controlled conditions was used to profile the surface silanol topochemistry and the occurrence of surface nearly free silanols on crystalline silica polymorphs. All crystalline silica polymorphs, but stishovite were membranolytic. Notably, pristine stishovite did not exhibited surface nearly free silanols. The topochemistry of surface silanols was modulated by thermal treatments, and we showed that the occurrence of nearly free silanols paralleled the membranolytic activity for the crystalline silica polymorphs. These results provide a comprehensive understanding of the structure-activity relationship between nearly free silanols and membranolytic activity of crystalline silica polymorphs, offering a possible clue for interpreting the molecular mechanisms associated with silica hazard and bio-minero-chemical interfacial phenomena, including prebiotic chemistry.
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Affiliation(s)
- Cristina Pavan
- Department of Chemistry, University of Turin, Turin, Italy,“G. Scansetti” Interdepartmental Centre for Studies on Asbestos and Other Toxic Particulates, University of Turin, Turin, Italy,Louvain Centre for Toxicology and Applied Pharmacology, Institute of Experimental and Clinical Research, Université catholique de Louvain, Brussels, Belgium
| | - Guillermo Escolano-Casado
- Department of Chemistry, University of Turin, Turin, Italy,Nanostructured Interfaces and Surfaces Interdepartmental Centre, University of Turin, Turin, Italy
| | - Chiara Bellomo
- Department of Chemistry, University of Turin, Turin, Italy,“G. Scansetti” Interdepartmental Centre for Studies on Asbestos and Other Toxic Particulates, University of Turin, Turin, Italy
| | - Stefania Cananà
- Department of Chemistry, University of Turin, Turin, Italy,“G. Scansetti” Interdepartmental Centre for Studies on Asbestos and Other Toxic Particulates, University of Turin, Turin, Italy
| | - Maura Tomatis
- Department of Chemistry, University of Turin, Turin, Italy,“G. Scansetti” Interdepartmental Centre for Studies on Asbestos and Other Toxic Particulates, University of Turin, Turin, Italy
| | - Riccardo Leinardi
- Louvain Centre for Toxicology and Applied Pharmacology, Institute of Experimental and Clinical Research, Université catholique de Louvain, Brussels, Belgium
| | - Lorenzo Mino
- Department of Chemistry, University of Turin, Turin, Italy,Nanostructured Interfaces and Surfaces Interdepartmental Centre, University of Turin, Turin, Italy
| | - Francesco Turci
- Department of Chemistry, University of Turin, Turin, Italy,“G. Scansetti” Interdepartmental Centre for Studies on Asbestos and Other Toxic Particulates, University of Turin, Turin, Italy,*Correspondence: Francesco Turci,
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Anderson SE, Shane H, Long C, Marrocco A, Lukomska E, Roberts JR, Marshall N, Fedan JS. Biological effects of inhaled hydraulic fracturing sand dust. VIII. Immunotoxicity. Toxicol Appl Pharmacol 2020; 408:115256. [PMID: 33007384 PMCID: PMC7796771 DOI: 10.1016/j.taap.2020.115256] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/23/2020] [Accepted: 09/26/2020] [Indexed: 11/28/2022]
Abstract
Hydraulic fracturing ("fracking") is a process used to enhance retrieval of gas from subterranean natural gas-laden rock by fracturing it under pressure. Sand used to stabilize fissures and facilitate gas flow creates a potential occupational hazard from respirable fracking sand dust (FSD). As studies of the immunotoxicity of FSD are lacking, the effects of whole-body inhalation (6 h/d for 4 d) of a FSD, i.e., FSD 8, was investigated at 1, 7, and 27 d post-exposure in rats. Exposure to 10 mg/m3 FSD 8 resulted in decreased lung-associated lymph node (LLN) cellularity, total B-cells, CD4+ T-cells, CD8+ T-cells and total natural killer (NK) cells at 7-d post exposure. The frequency of CD4+ T-cells decreased while the frequency of B-cells increased (7 and 27 d) in the LLN. In contrast, increases in LLN cellularity and increases in total CD4+ and CD8+ T-cells were observed in rats following 30 mg/m3 FSD 8 at 1 d post-exposure. Increases in the frequency and number of CD4+ T-cells and NK cells were observed in bronchial alveolar lavage fluid at 7-d post-exposure (10 mg/m3) along with an increase in total CD4+ T-cells, CD11b + cells, and NK cells at 1-day post-exposure (30 mg/m3). Increases in the numbers of B-cells and CD8+ T-cells were observed in the spleen at 1-day post 30 mg/m3 FSD 8 exposure. In addition, NK cell activity was suppressed at 1 d (30 mg/m3) and 27 d post-exposure (10 mg/m3). No change in the IgM response to sheep red blood cells was observed. The findings indicate that FSD 8 caused alterations in cellularity, phenotypic subsets, and impairment of immune function.
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Affiliation(s)
- Stacey E Anderson
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, United States of America.
| | - Hillary Shane
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, United States of America
| | - Carrie Long
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, United States of America
| | - Antonella Marrocco
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, United States of America
| | - Ewa Lukomska
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, United States of America
| | - Jenny R Roberts
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, United States of America
| | - Nikki Marshall
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, United States of America
| | - Jeffrey S Fedan
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, United States of America
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Pavan C, Fubini B. Unveiling the Variability of “Quartz Hazard” in Light of Recent Toxicological Findings. Chem Res Toxicol 2016; 30:469-485. [DOI: 10.1021/acs.chemrestox.6b00409] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Cristina Pavan
- Department of Chemistry, University of Torino, Via P. Giuria 7, 10125 Turin, Italy
- “G. Scansetti” Interdepartmental
Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 9, 10125 Turin, Italy
| | - Bice Fubini
- Department of Chemistry, University of Torino, Via P. Giuria 7, 10125 Turin, Italy
- “G. Scansetti” Interdepartmental
Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 9, 10125 Turin, Italy
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Di Benedetto F, Gazzano E, Tomatis M, Turci F, Pardi LA, Bronco S, Fornaciai G, Innocenti M, Montegrossi G, Muniz Miranda M, Zoleo A, Capacci F, Fubini B, Ghigo D, Romanelli M. Physico-chemical properties of quartz from industrial manufacturing and its cytotoxic effects on alveolar macrophages: The case of green sand mould casting for iron production. JOURNAL OF HAZARDOUS MATERIALS 2016; 312:18-27. [PMID: 27015375 DOI: 10.1016/j.jhazmat.2016.03.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 02/17/2016] [Accepted: 03/05/2016] [Indexed: 06/05/2023]
Abstract
Industrial processing of materials containing quartz induces physico-chemical modifications that contribute to the variability of quartz hazard in different plants. Here, modifications affecting a quartz-rich sand during cast iron production, have been investigated. Composition, morphology, presence of radicals associated to quartz and reactivity in free radical generation were studied on a raw sand and on a dust recovered after mould dismantling. Additionally, cytotoxicity of the processed dust and ROS and NO generation were evaluated on MH-S macrophages. Particle morphology and size were marginally affected by casting processing, which caused only a slight increase of the amount of respirable fraction. The raw sand was able to catalyze OH and CO2(-) generation in cell-free test, even if in a lesser extent than the reference quartz (Min-U-Sil), and shows hAl radicals, conventionally found in any quartz-bearing raw materials. Enrichment in iron and extensive coverage with amorphous carbon were observed during processing. They likely contributed, respectively, to increasing the ability of processed dust to release CO2- and to suppressing OH generation respect to the raw sand. Carbon coverage and repeated thermal treatments during industrial processing also caused annealing of radiogenic hAl defects. Finally, no cellular responses were observed with the respirable fraction of the processed powder.
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Affiliation(s)
- Francesco Di Benedetto
- Department of Earth Sciences, Università di Firenze, Firenze, Italy; Institute of Geosciences and Earth Resources (CNR-IGG), Florence, Italy.
| | - Elena Gazzano
- Department of Oncology, Università degli studi di Torino, Torino, Italy; "G. Scansetti" Interdepartmental Center for Studies on Asbestos and other Toxic Particulates, Università degli studi di Torino, Torino, Italy
| | - Maura Tomatis
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and other Toxic Particulates, Università degli studi di Torino, Torino, Italy; Department of Chemistry, Università degli studi di Torino, Torino, Italy
| | - Francesco Turci
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and other Toxic Particulates, Università degli studi di Torino, Torino, Italy; Department of Chemistry, Università degli studi di Torino, Torino, Italy
| | - Luca A Pardi
- Institute for Chemical and Physical processes (CNR-IPCF), Pisa, Italy
| | - Simona Bronco
- Institute for Chemical and Physical processes (CNR-IPCF), Pisa, Italy
| | | | - Massimo Innocenti
- Department of Chemistry, Università di Firenze, Sesto Fiorentino, Italy
| | | | | | - Alfonso Zoleo
- Department of Chemical Sciences, Università di Padova, Padova, Italy
| | | | - Bice Fubini
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and other Toxic Particulates, Università degli studi di Torino, Torino, Italy; Department of Chemistry, Università degli studi di Torino, Torino, Italy
| | - Dario Ghigo
- Department of Oncology, Università degli studi di Torino, Torino, Italy; "G. Scansetti" Interdepartmental Center for Studies on Asbestos and other Toxic Particulates, Università degli studi di Torino, Torino, Italy
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Turci F, Pavan C, Leinardi R, Tomatis M, Pastero L, Garry D, Anguissola S, Lison D, Fubini B. Revisiting the paradigm of silica pathogenicity with synthetic quartz crystals: the role of crystallinity and surface disorder. Part Fibre Toxicol 2016; 13:32. [PMID: 27286702 PMCID: PMC4902968 DOI: 10.1186/s12989-016-0136-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/05/2016] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Exposure to some - but not all - quartz particles is associated to silicosis, lung cancer and autoimmune diseases. What imparts pathogenicity to any single quartz source is however still unclear. Crystallinity and various surface features are implied in toxicity. Quartz dusts used so far in particle toxicology have been obtained by grinding rocks containing natural quartz, a process which affects crystallinity and yields dusts with variable surface states. To clarify the role of crystallinity in quartz pathogenicity we have grown intact quartz crystals in respirable size. METHODS Quartz crystals were grown and compared with a fractured specimen obtained by grinding the largest synthetic crystals and a mineral quartz (positive control). The key physico-chemical features relevant to particle toxicity - particle size distribution, micromorphology, crystallinity, surface charge, cell-free oxidative potential - were evaluated. Membranolysis was assessed on biological and artificial membranes. Endpoints of cellular stress were evaluated on RAW 264.7 murine macrophages by High Content Analysis after ascertaining cellular uptake by bio-TEM imaging of quartz-exposed cells. RESULTS Quartz crystals were grown in the submicron (n-Qz-syn) or micron (μ-Qz-syn) range by modulating the synthetic procedure. Independently from size as-grown quartz crystals with regular intact faces did not elicit cellular toxicity and lysosomal stress on RAW 264.7 macrophages, and were non-membranolytic on liposome and red blood cells. When fractured, synthetic quartz (μ-Qz-syn-f) attained particle morphology and size close to the mineral quartz dust (Qz-f, positive control) and similarly induced cellular toxicity and membranolysis. Fracturing imparted a higher heterogeneity of silanol acidic sites and radical species at the quartz surface. CONCLUSIONS Our data support the hypothesis that the biological activity of quartz dust is not due to crystallinity but to crystal fragmentation, when conchoidal fractures are formed. Besides radical generation, fracturing upsets the expected long-range order of non-radical surface moieties - silanols, silanolates, siloxanes - which disrupt membranes and induce cellular toxicity, both outcomes associated to the inflammatory response to quartz.
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Affiliation(s)
- Francesco Turci
- Department of Chemistry, University of Torino, Via P. Giuria 7, Turin, 10125, Italy.
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, Turin, 10125, Italy.
| | - Cristina Pavan
- Department of Chemistry, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
| | - Riccardo Leinardi
- Department of Chemistry, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
| | - Maura Tomatis
- Department of Chemistry, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
| | - Linda Pastero
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
- Department of Earth Sciences, University of Torino, Via V. Caluso 35, Turin, 10125, Italy
| | - David Garry
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin, Dublin, Belfield, Ireland
| | - Sergio Anguissola
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin, Dublin, Belfield, Ireland
| | - Dominique Lison
- Louvain centre for Toxicology and Applied Pharmacology (LTAP), Université catholique de Louvain, Avenue E. Mounier 52 - bte B1.52.12, Brussels, 1200, Belgium
| | - Bice Fubini
- Department of Chemistry, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, Turin, 10125, Italy
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Pavan C, Polimeni M, Tomatis M, Corazzari I, Turci F, Ghigo D, Fubini B. Editor's Highlight: Abrasion of Artificial Stones as a New Cause of an Ancient Disease. Physicochemical Features and Cellular Responses. Toxicol Sci 2016; 153:4-17. [DOI: 10.1093/toxsci/kfw101] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Pavan C, Rabolli V, Tomatis M, Fubini B, Lison D. Why does the hemolytic activity of silica predict its pro-inflammatory activity? Part Fibre Toxicol 2014; 11:76. [PMID: 25522817 PMCID: PMC4318150 DOI: 10.1186/s12989-014-0076-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 12/11/2014] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND The hemolytic activity of inhaled particles such as silica has been widely investigated in the past and represents a usual toxicological endpoint to characterize particle reactivity despite the fact that red blood cells (RBCs) are not involved in the pathogenesis of pulmonary inflammation or fibrosis caused by some inhaled particles. The inflammatory process induced by silica starts with the activation of the inflammasome, which leads to the release of mature IL-1β. One of the upstream mechanisms causing activation of the inflammasome is the labilization of the phagolysosomal membrane after particle phagocytosis. Considering RBC lysis as a model of membrane damage, we evaluated the relationship between hemolytic activity and inflammasome-dependent release of IL-1β for a panel of selected silica particles, in search of the toxicological significance of the hemolytic activity of an inhaled particle. METHODS Well-characterized silica particles, including four quartz samples and a vitreous silica, with different surface properties and hemolytic potential were tested for their capacity to induce inflammasome-dependent release of IL-1β in LPS-primed primary murine peritoneal macrophages by ELISA and Western blot analysis. The mechanisms of IL-1β maturation and release were clarified by using ASC-deficient cells and inhibitors of phagocytosis and cathepsin B. RESULTS The silica samples induced dose-dependent hemolysis and IL-1β release of different amplitudes. A significant correlation between IL-1β release and hemolytic activity was evidenced (r = 0.827) by linear regression analysis. IL-1β release was completely abolished in ASC-deficient cells and reduced by inhibitors, confirming the involvement of the inflammasome and the requirement of phagocytosis and cathepsin B for activation. CONCLUSIONS The same physico-chemical properties of silica particles which are relevant for the lysis of the RBC membrane also appear implicated in the labilization of the phagolysosome, leading to inflammasome activation and release of the pro-inflammatory cytokine IL-1β. These findings strengthen the relevance of the hemolysis assay to predict the pro-inflammatory activity of silica dusts.
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Affiliation(s)
- Cristina Pavan
- Department of Chemistry, "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, 10125, Turin, Italy.
| | - Virginie Rabolli
- Louvain Center for Toxicology and Applied Pharmacology (LTAP), Université catholique de Louvain, Avenue E. Mounier 52 - bte B1.52.12, 1200, Brussels, Belgium.
| | - Maura Tomatis
- Department of Chemistry, "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, 10125, Turin, Italy.
| | - Bice Fubini
- Department of Chemistry, "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino, Via P. Giuria 7, 10125, Turin, Italy.
| | - Dominique Lison
- Louvain Center for Toxicology and Applied Pharmacology (LTAP), Université catholique de Louvain, Avenue E. Mounier 52 - bte B1.52.12, 1200, Brussels, Belgium.
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Qiu Y, Wang Z, Owens ACE, Kulaots I, Chen Y, Kane AB, Hurt RH. Antioxidant chemistry of graphene-based materials and its role in oxidation protection technology. NANOSCALE 2014; 6:11744-55. [PMID: 25157875 PMCID: PMC4312421 DOI: 10.1039/c4nr03275f] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Two-dimensional nanomaterials have potential as a new class of antioxidants that combine physical barrier function with ultrahigh surface area for free radical scavenging. This work presents the first measurements of the chemical reactivities of graphene-based materials toward a set of model free radicals and reactive oxygen species using electron paramagnetic resonance spectroscopy (EPR) and sacrificial dye protection assays. Graphene-based materials are shown to protect a variety of molecular targets from oxidation by these species, and to be highly effective as hydroxyl-radical scavengers. When the hydroxyl radical is produced photolytically, the overall antioxidant effect is a combination of preventative antioxidant activity (UV absorption) and ˙OH radical scavenging. Few-layer graphene is more active than monolayer graphene oxide, despite its lower surface area, which indicates that the primary scavenging sites are associated with the sp(2)-carbon network rather than oxygen-containing functional groups. To explain this trend, we propose that GO is a weak hydrogen donor, due to the non-phenolic nature of most OH groups on GO, which reside at basal sp(3)-carbon sites that do not allow for radical resonance stabilization following hydrogen donation. As an example application of graphene antioxidant behavior, we show that encapsulation of TiO2 nanoparticles in graphene nanosacks reduces undesired photo-oxidative damage to nearby organic target molecules, which suggests graphene encapsulation as a new approach to managing adverse environmental or health impacts of redox-active nanomaterials.
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Affiliation(s)
- Yang Qiu
- School of Engineering, Brown University, Providence, RI 02912, USA.
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Pavan C, Tomatis M, Ghiazza M, Rabolli V, Bolis V, Lison D, Fubini B. In search of the chemical basis of the hemolytic potential of silicas. Chem Res Toxicol 2013; 26:1188-98. [PMID: 23819533 DOI: 10.1021/tx400105f] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The membranolytic activity of silica particles toward red blood cells (RBCs) has been known for a long time and is sometimes associated with silica pathogenicity. However, the molecular mechanism and the reasons why hemolysis differs according to the silica form are still obscure. A panel of 15 crystalline (pure and commercial) and amorphous (pyrogenic, precipitated from aqueous solutions, vitreous) silica samples differing in size, origin, morphology, and surface chemical composition were selected and specifically prepared. Silica particles were grouped into six groups to compare their potential in disrupting RBC membranes so that one single property differed in each group, while other features were constant. Free radical production and crystallinity were not strict determinants of hemolytic activity. Particle curvature and morphology modulated the hemolytic effect, but silanols and siloxane bridges at the surface were the main actors. Hemolysis was unrelated to the overall concentration of silanols as fully rehydrated surfaces (such as those obtained from aqueous solution) were inert, and one pyrogenic silica also lost its membranolytic potential upon progressive dehydration. Overall results are consistent with a model whereby hemolysis is determined by a defined surface distribution of dissociated/undissociated silanols and siloxane groups strongly interacting with specific epitopes on the RBC membrane.
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Affiliation(s)
- Cristina Pavan
- "G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, Department of Chemistry, University of Torino , Via P. Giuria 7, 10125 Turin, Italy
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