Nanotoxicology Of Metal Oxide Nanoparticles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This review discusses recent advances in the synthesis, characterization and toxicity of metal oxide nanoparticles obtained mainly through biogenic (green) processes. The in vitro and in vivo toxicities of these oxides are discussed including a consideration of the factors important for safe use of these nanomaterials. The toxicities of different metal oxide nanoparticles are compared. The importance of biogenic synthesized metal oxide nanoparticles has been increasing in recent years; however, more studies aimed at better characterizing the potent toxicity of these nanoparticles are still necessary for nanosafely considerations and environmental perspectives. In this context, this review aims to inspire new research in the design of green approaches to obtain metal oxide nanoparticles for biomedical and technological applications and to highlight the critical need to fully investigate the nanotoxicity of these particles.52934975Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)NanoBioss (MCTI)Brazilian Network on NanotoxicologyFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Mindfulness and other simple neuroscience-based proposals to promote the learning performance and mental health of students during the COVID-19 pandemic

The COVID-19 pandemic has had a negative impact on education. The restrictions imposed have undoubtedly led to impairment of the psychological well-being of both teachers and students, and of the way they experience interpersonal relationships. As reported previously in the literature, adverse effects such as loneliness, anxiety, and stress have resulted in a decrease in the cognitive performance of school and higher education students. Therefore, the objective of this work is to present a general overview of the reported adverse effects of the COVID-19 pandemic which may potentially influence the learning performance of students. Some neuroscientific findings related to memory and cognition, such as neuroplasticity and long-term potentiation, are also shown. We also discuss the positive effects of the practice of mindfulness, as well as other simple recommendations based on neuroscientific findings such as restful sleep, physical activity, and nutrition, which can act on memory and cognition. Finally, we propose some practical recommendations on how to achieve The COVID-19 pandemic has had a negative impact on education. The restrictions imposed have undoubtedly led to impairment of the psychological well-being of both teachers and students, and of the way they experience interpersonal relationships. As reported previously in the literature, adverse effects such as loneliness, anxiety, and stress have resulted in a decrease in the cognitive performance of school and higher education students. Therefore, the objective of this work is to present a general overview of the reported adverse effects of the COVID-19 pandemic which may potentially influence the learning performance of students. Some neuroscientific findings related to memory and cognition, such as neuroplasticity and long-term potentiation, are also shown. We also discuss the positive effects of the practice of mindfulness, as well as other simple recommendations based on neuroscientific findings such as restful sleep, physical activity, and nutrition, which can act on memory and cognition. Finally, we propose some practical recommendations on how to achieve more effective student learning in the context of the pandemic. The aim of this review is to provide some assistance in this changing and uncertain situation in which we all find ourselves, and we hope that some of the information could serve as a starting point for hypotheses to be tested in educational research and their association with neuroscience.This research was funded by the Dirección de Investigación-Universidad de La Frontera (DI20-1003) and Project Covid (73) Process number: 23006.002357/2020-20—Universidade Federal do ABC. In addition, this work was partially funded by FEDER funds through the Operational Competitiveness Program—COMPETE and by National Funds through Fundação para a Ciência e Tecnologia (FCT)—under the projects PTDC/CTM-TEX/28295/2017 and UID/CTM/00264/2019

Synthesis, characterization and cytotoxicity of S-nitrosomercaptosuccinic acid-containing alginate/chitosan nanoparticles

Nitric oxide (NO) is an endogenous free radical, which plays key roles in several biological processes including vasodilation, neurotransmission, inhibition of platelet adhesion, cytotoxicity against pathogens, wound healing, and defense against cancer. Due to the relative instability of NO in vivo (half-life of ca. 0.5 seconds), there is an increasing interest in the development of low molecular weight NO donors, such as S-nitrosothiols (RSNOs), which are able to prolong and preserve the biological activities of NO in vivo. In order to enhance the sustained NO release in several biomedical applications, RSNOs have been successfully allied to nanomaterials. In this context, this work describes the synthesis and characterization of the NO donor S-nitroso-mercaptosuccinic acid (S-nitroso-MSA), which belongs to the class of RSNOs, and its incorporation in polymeric biodegradable nanoparticles composed by alginate/chitosan. First, chitosan nanoparticles were obtained by gelation process with sodium tripolyphosphate (TPP), followed by the addition of the alginate layer, to enhance the nanoparticle protection. The obtained nanoparticles presented a hydrodynamic diameter of 343 +/- 38 nm, polydispersity index (PDI) of 0.36 +/- 0.1, and zeta potential of -30.3 +/- 0.4 mV, indicating their thermal stability in aqueous suspension. The negative zeta potential value was assigned to the presence of alginate chains on the surface of chitosan/TPP nanoparticles. The encapsulation efficiency of the NO donor into the polymeric nanoparticles was found to be 98 +/- 0.2%. The high encapsulation efficiency value was attributed to the positive interactions between the NO donor and the polymeric content of the nanoparticles. Kinetics of NO release from the nanoparticles revealed a spontaneous and sustained release of therapeutic amounts of NO, for several hours under physiological temperature. The incubation of NO-releasing alginate/chitosan nanoparticles with human hepatocellular carcinoma (HepG2) cell line revealed a concentration-dependent toxicity. These results point to the promising uses of NO-releasing alginate/chitosan nanoparticles for anti-cancer chemotherapy.Brazilian Network on NanotoxicologyLaboratory of Nanostructure Synthesis and Biosystem Interactions-NANOBIOSS (MCTI)Newton Advanced Fellowship (The Royal Society)Univ Fed ABC, Ctr Nat & Human Sci, Av Estados 5001, BR-09210580 Santo Andre, SP, BrazilUniv Fed Sao Paulo, Exact & Earth Sci Dept, Rua Sao Nicolau 210, BR-09913030 Diadema, SP, BrazilUniv Fed Sao Paulo, Exact & Earth Sci Dept, Rua Sao Nicolau 210, BR-09913030 Diadema, SP, BrazilBrazilian Network on Nanotoxicology: 52120/2011-1Laboratory of Nanostructure Synthesis and Biosystem Interactions-NANOBIOSS (MCTI): 402280-2013Newton Advanced Fellowship (The Royal Society): NA140046Web of Scienc

In vitro inhibition of linoleic acid peroxidation by primary S-nitrosothiols

Nitric oxide ( NO) is an effective chain-breaking antioxidant in the inhibition of lipid peroxidation and circulates in vivo mainly as primary S-nitrosothiols (RSNOs). In this work, the in vitro peroxidation of linoleic acid-SDS comicelles (LA-SDS) catalyzed by soybean lipoxygenase (SLO) and FeII ions was monitored in the presence and absence of three primary RSNOs: S-nitrosocysteine, S-nitroso-N-acetylcysteyne and S-nitrosoglutathione. Kinetic measurements based on the formation of conjugated double bonds and fluorescent oxidized LA-lysine adducts, showed that RSNOs are more potent antioxidants than their corresponding free thiols (RSHs) in equimolar conditions. These results are consistent with the blocking of LA-SDS peroxidation by RSNOs through the inactivation of peroxyl/alkoxyl (LOO /LO ) radicals, leading to nitrogen-containing products of oxidized LA, which release free NO. These results indicate that endogenous RSNOs may play a major role in the blocking of lipid peroxidation in vivo, through the primary inactivation of alkoxyl/peroxyl radicals and also of preformed lipid hydroperoxides.O óxido nítrico ( NO) é um antioxidante efetivo na inibição da peroxidação lipídica e circula in vivo principalmente como S-nitrosotióis primários (RSNOs). Neste trabalho, a peroxidação in vitro de comicelas do ácido linileico-SDS (LA-SDS) catalisada por lipoxigenase de soja (SLO) e íons FeII foi monitorada na presença e na ausência de três RSNOs: S-nitrosocisteína, S-nitroso-N-acetilcisteína e S-nitrosoglutationa. Medidas cinéticas baseadas na formação de duplas ligações conjugadas e adutos fluorescentes de lisina-La oxidado mostraram que os RSNOs são antioxidantes mais potentes que seus tióis livres (RSHs) correspondentes em condições equimolares. Esses resultados são consistentes com o bloqueio da peroxidação de LA-SDS por RSNOs através da inativação dos radicais peroxila/alcoxila (LOO /LO ), levando a produtos nitrogenados do LA oxidado, os quais liberam NO. Esses resultados indicam que os RSNOs endógenos podem desempenhar um papel importante no bloqueio da peroxidação lipídica in vivo, através da inativação primária de radicais alcoxila/peroxila bem como de hidroperóxidos lipídicos pré-formados.18851895Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Antibacterial activity of nitric oxide releasing silver nanoparticles

Silver nanoparticles (AgNPs) are well known potent antimicrobial agents. Similarly, the free radical nitric oxide (NO) has important antibacterial activity, and due to its instability, the combination of NO and nanomaterials has been applied in several biomedical applications. The aim of this work was to synthesize, characterize and evaluate the antibacterial activity of a new NO-releasing AgNPs. Herein, AgNPs were synthesized by the reduction of silver ions (Ag+) by catechin, a natural polyphenol and potent antioxidant agent, derived from green tea extract. Catechin acts as a reducing agent and as a capping molecule on the surface of AgNPs, minimizing particle agglomeration. The as-synthesized nanoparticles were characterized by different techniques. The results showed the formation of AgNPs with average hydrodynamic size of 44 nm, polydispersity index of 0.21, and zeta potential of -35.9 mV. X-ray diffraction and Fourier transform infrared spectroscopy revealed the presence of the AgNP core and cathecin as capping agent. The low molecular weight mercaptosuccinic acid (MSA), which contain free thiol group, was added on the surface of catechin-AgNPs, leading to the formation of MSA-catechin-AgNPs (the NO precursor nanoparticle). Free thiol groups of MSA-catechin-AgNPs were nitrosated leading to the formation of S-nitroso-mercaptosuccinic acid (S-nitroso-MSA), the NO donor. The amount of 342 +/- 16 mu mol of NO was released per gram of S-nitroso-MSA-catechin-AgNPs. The antibacterial activities of catechin-AgNPs, MSA-catechinAgNPs, and S-nitroso-MSA-catechin-AgNPs were evaluated towards different resistant bacterial strains. The results demonstrated an enhanced antibacterial activity of the NO-releasing AgNP. For instance, the minimal inhibitory concentration values for Pseudomonas aeruginosa (ATCC 27853) incubated with AgNPs-catechin, AgNPs-catechin-MSA, and AgNPs-catechin-S-nitroso-MSA were found to be 62, 125 and 3 mu g/mL, respectively. While in the case of Klebsiella pneumoniae (ATCC 700603) the minimum bactericidal concentration values for treatments with AgNPs-catechin, AgNPs-catechin-MSA, and AgNPs-catechin-Snitroso- MSA were found to be 1000, 500, and 125 mu g/mL, respectively. The antibacterial actions of the NO-releasing nanoparticle were superior in comparison with the antibacterial effects of AgNPs, in most of the tested antibiotic resistant bacteria strains. These results highlight the promising uses of NO-releasing AgNPs against resistant bacteria in several biomedical applications.Brazilian Network on Nanotoxicology (MCTI/CNPq)Laboratory of Nanostructure Synthesis and Biosystem Interactions-NANOBIOSS (MCTI)FONDECYTCONICYT REDESUniv Fed ABC, Ctr Nat & Human Sci, Santo Andre, SP, BrazilUniv Fed Sao Paulo, Exact & Earth Sci Dept, Diadema, SP, BrazilUniv La Frontera, Chem Engn Dept, Temuco, ChileUniv Estadual Campinas, Inst Biol, Trop Dis Lab, Campinas, SP, BrazilUniv Estadual Campinas, Biol Chem Lab, Inst Chem, Campinas, SP, BrazilLNNano CNPEM, Campinas, SP, BrazilUniv Fed Sao Paulo, Exact & Earth Sci Dept, Diadema, SP, BrazilBrazilian Network on Nanotoxicology (MCTI/CNPq): 552120/2011-1Laboratory of Nanostructure Synthesis and Biosystem Interactions-NANOBIOSS (MCTI): 402280-2013FONDECYT: 1130854CONICYT REDES: 140053Web of Scienc

In vitro inhibition of linoleic acid peroxidation by primary S-nitrosothiols

Nitric oxide (•NO) is an effective chain-breaking antioxidant in the inhibition of lipid peroxidation and circulates in vivo mainly as primary S-nitrosothiols (RSNOs). In this work, the in vitro peroxidation of linoleic acid-SDS comicelles (LA-SDS) catalyzed by soybean lipoxygenase (SLO) and FeII ions was monitored in the presence and absence of three primary RSNOs: S-nitrosocysteine, S-nitroso-N-acetylcysteyne and S-nitrosoglutathione. Kinetic measurements based on the formation of conjugated double bonds and fluorescent oxidized LA-lysine adducts, showed that RSNOs are more potent antioxidants than their corresponding free thiols (RSHs) in equimolar conditions. These results are consistent with the blocking of LA-SDS peroxidation by RSNOs through the inactivation of peroxyl/alkoxyl (LOO•/LO•) radicals, leading to nitrogen-containing products of oxidized LA, which release free •NO. These results indicate that endogenous RSNOs may play a major role in the blocking of lipid peroxidation in vivo, through the primary inactivation of alkoxyl/peroxyl radicals and also of preformed lipid hydroperoxides

Nanoparticulated Nitric Oxide Donors And Their Biomedical Applications

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The small molecule nitric oxide (NO) plays important roles in many vital physiological and pathophysiological processes, including the modulation of cardiovascular processes, and key functions in the immune, nervous e respiratory systems. Several pathological conditions, such as sexual dysfunction and hypertension, are associated with deficiencies in the NO production or its inactivation. Due to the relative instability of NO in biological system, there is an increasing interest in the preparation of NO carriers as an efficient platform to carry and deliver therapeutic and relevant amounts of NO in biomedical applications. Among these approaches, NO-releasing nanomaterials have been described as promising strategy that could promote the spatio-temporal production of NO, in several pharmacological applications. The scope of this review is to point out the recent advances in the synthesis of versatile NO-releasing nanomaterials based on several materials, including polymeric nanoparticles, dendrimers, liposomes, solid lipid nanoparticles, metallic nanoparticles, silica nanoparticles, and carbon nanotubes. Although important progress in this area, some drawbacks still need to be overcome in order to translate these research innovations into practical applications. In this scenario, this review describes the state of the art of versatile nanostructured NO donors and their biomedical applications.173216223FAPESPCNPqINOMAT (MCTI/CNPq)NanoBioss (MCTI)Brazilian Network on Nanotoxicology (MCTI/CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq