Comparative in vitro toxicity of a graphene oxide-silver nanocomposite and the pristine counterparts toward macrophages

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Graphene oxide (GO) is a highly oxidized graphene form with oxygen functional groups on its surface. GO is an excellent platform to support and stabilize silver nanoparticles (AgNP), which gives rise to the graphene oxide-silver nanoparticle (GOAg) nanocomposite. Understanding how this nanocomposite interacts with cells is a toxicological challenge of great importance for future biomedical applications, and macrophage cells can provide information concerning the biocompatibility of these nanomaterials. The cytotoxicity of the GOAg nanocomposite, pristine GO, and pristine AgNP was compared toward two representative murine macrophages: a tumoral lineage (J774) and peritoneal macrophages collected from Balb/c mouse. The production of reactive oxygen species (ROS) by J774 macrophages was also monitored. We investigated the internalization of nanomaterials by transmission electron microscopy (TEM). The quantification of internalized silver was carried out by inductively coupled plasma mass spectrometry (ICP-MS). Nanomaterial stability in the cell media was investigated overtime by visual observation, inductively coupled plasma optical emission spectrometry (ICP OES), and dynamic light scattering (DLS). Results: The GOAg nanocomposite was more toxic than pristine GO and pristine AgNP for both macrophages, and it significantly induced more ROS production compared to pristine AgNP. TEM analysis showed that GOAg was internalized by tumoral J774 macrophages. However, macrophages internalized approximately 60 % less GOAg than did pristine AgNP. The images also showed the degradation of nanocomposite inside cells. Conclusions: Although the GOAg nanocomposite was less internalized by the macrophage cells, it was more toxic than the pristine counterparts and induced remarkable oxidative stress. Our findings strongly reveal a synergistic toxicity effect of the GOAg nanocomposite. The toxicity and fate of nanocomposites in cells are some of the major concerns in the development of novel biocompatible materials and must be carefully evaluated.Graphene oxide (GO) is a highly oxidized graphene form with oxygen functional groups on its surface. GO is an excellent platform to support and stabilize silver nanoparticles (AgNP), which gives rise to the graphene oxide-silver nanoparticle (GOAg) nanoco14CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)140560/2014-9The authors thank the National Council for Technological and Scientific Development (CNPq) for the PhD student scholarship (140560/2014-9) and the financial support. The authors also acknowledge Dr. Daniel Ruiz Abanádes for suggestions, Renata Magueta fo

Nano silver vanadate AgVO3: Synthesis, new functionalities and applications

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOSilver vanadates have been widely investigated because of their many interesting properties and their potential use in several applications. In addition to this, a large number of groups have investigated silver vanadates in the form of nanostructures. He187973985CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOSEM INFORMAÇÃOThe authors thank the National Council for Technological and Scientific Development (CNPq), the Laboratory of Synthesis of Nanostructures and Interaction with Biosystems (NanoBioss), and the National Institute of Science Technology and Innovation in Comp

Hazard Assessment of Abraded Thermoplastic Composites Reinforced with Reduced Graphene Oxide

Graphene-related materials (GRMs) are subject to intensive investigations and considerable progress has been made in recent years in terms of safety assessment. However, limited information is available concerning the hazard potential of GRM-containing products such as graphene-reinforced composites. In the present study, we conducted a comprehensive investigation of the potential biological effects of particles released through an abrasion process from reduced graphene oxide (rGO)-reinforced composites of polyamide 6 (PA6), a widely used engineered thermoplastic polymer, in comparison to as-produced rGO. First, a panel of well-established in vitro models, representative of the immune system and possible target organs such as the lungs, the gut, and the skin, was applied. Limited responses to PA6-rGO exposure were found in the different in vitro models. Only as-produced rGO induced substantial adverse effects, in particular in macrophages. Since inhalation of airborne materials is a key occupational concern, we then sought to test whether the in vitro responses noted for these materials would translate into adverse effects in vivo. To this end, the response at 1, 7 and 28 days after a single pulmonary exposure was evaluated in mice. In agreement with the in vitro data, PA6-rGO induced a modest and transient pulmonary inflammation, resolved by day 28. In contrast, rGO induced a longer-lasting, albeit moderate inflammation that did not lead to tissue remodeling within 28 days. Taken together, the present study suggests a negligible impact on human health under acute exposure conditions of GRM fillers such as rGO when released from composites at doses expected at the workplace

Evaluation of antileishmanial drugs activities in an ex vivo model of leishmaniasis

Leishmaniasis is a poverty-related disease, the chemotherapy of which is based on few drugs. The in vitro macrophage-amastigote model using mouse peritoneal cells, human-monocyte transformed macrophages and immortalized cell lines have been used to test new and safe antileishmanial drugs. Considering the differences for drug sensitivities between these Leishmania infected cells, the efficacy of amphotericin B, pentavalent antimonial, miltefosine and resveratrol was evaluated in a recently developed ex vivo culture of macrophages isolated from mouse lesion induced by L. amazonensis (CD11b(+)F4/80(+)CD68(+)CD14(+)) compared with infected peritoneal macrophages (CD11b(+)F4/80(+)CD68(+)CD14(+)). The results show that IC50 values of amphotericin B, miltefosine and pentavalent antimonial for parasites in lesional and peritoneal macrophages were similar, although high doses of these compounds did not result in total clearance of parasites in lesional cells (amphotericin B), peritoneal cells (miltefosine) and both cell cultures (pentavalent antimonial). Amastigotes infecting lesional macrophages were more resistant to resveratrol as compared to parasites in peritoneal macrophages. The cytoxicity of miltefosine and resveratrol was higher in infected peritoneal macrophages than in lesional cells. These data suggest that the antileishmanial effect and citotoxicity of some anti leishmanial compounds are dependent of macrophage source and mouse peritoneal macrophages loaded with amastigotes do not represent the lesion cell71163166CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP405581/2018não tem2018/23302-

Long-term cell culture isolated from lesions of mice infected with leishmania amazonensis: a new approach to study mononuclear phagocyte subpopulations during the infection

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESLeishmanioses are neglected diseases and the parasite Leishmania survives and proliferates within mononuclear phagocytes, particularly macrophages. In vitro studies of the immunology and cell biology of leishmaniosis are performed in murine peritoneum and75818CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESsem informaçãosem informaçãosem informaçãoThis work was supported by the National Council for Scientific and Technological Development (CNPq), the Sao Paulo Researc Foundation (FAPESP) and the Coordination of Improvement of Higher Education Personnel (CAPES

Lung Persistence, Biodegradation and Elimination of Graphene Based Materials is Predominantly Size-Dependent and Mediated by Alveolar Phagocytes

Graphene-based materials (GBMs) have promising applications in various sectors, including pulmonary nanomedicine. Nevertheless, the influence of GBM physicochemical characteristics on their fate and impact in lung has not been thoroughly addressed. To fill this gap, the biological response, distribution, and bio-persistence of four different GBMs in mouse lungs up to 28 days after single oropharyngeal aspiration are investigated. None of the GBMs, varying in size (large versus small) and carbon to oxygen ratio as well as thickness (few-layers graphene (FLG) versus thin graphene oxide (GO)), induce a strong pulmonary immune response. However, recruited neutrophils internalize nanosheets better and degrade GBMs faster than macrophages, revealing their crucial role in the elimination of small GBMs. In contrast, large GO sheets induce more damages due to a hindered degradation and long-term persistence in macrophages. Overall, small dimensions appear to be a leading feature in the design of safe GBM pulmonary nanovectors due to an enhanced degradation in phagocytes and a faster clearance from the lungs for small GBMs. Thickness also plays an important role, since decreased material loading in alveolar phagocytes and faster elimination are found for FLGs compared to thinner GOs. These results are important for designing safer-by-design GBMs for biomedical application

Innate but not adaptive immunity regulates lung recovery from chronic exposure to graphene oxide nanosheets

Altres ajuts: the ICN2 is funded by the CERCA programme, Generalitat de Catalunya.Graphene has drawn a lot of interest in the material community due to unique physicochemical properties. Owing to a high surface area to volume ratio and free oxygen groups, the oxidized derivative, graphene oxide (GO) has promising potential as a drug delivery system. Here, the lung tolerability of two distinct GO varying in lateral dimensions is investigated, to reveal the most suitable candidate platform for pulmonary drug delivery. Following repeated chronic pulmonary exposure of mice to GO sheet suspensions, the innate and adaptive immune responses are studied. An acute and transient influx of neutrophils and eosinophils in the alveolar space, together with the replacement of alveolar macrophages by interstitial ones and a significant activation toward anti-inflammatory subsets, are found for both GO materials. Micrometric GO give rise to persistent multinucleated macrophages and granulomas. However, neither adaptive immune response nor lung tissue remodeling are induced after exposure to micrometric GO. Concurrently, milder effects and faster tissue recovery, both associated to a faster clearance from the respiratory tract, are found for nanometric GO, suggesting a greater lung tolerability. Taken together, these results highlight the importance of dimensions in the design of biocompatible 2D materials for pulmonary drug delivery system