Efficient and Durable Vaccine against Intimin �� of Diarrheagenic E. Coli Induced by Clay Nanoparticles

Improved strategies are urgently required to control infections with enterohemorrhagic Escherichia coli and enteropathogenic E. coli, two dominant zoonotic enteric pathogens responsible for a wide spectrum of illnesses as well as deaths of human being, with tremendous financial cost worldwide. The present study investigates the capacity of two clay nanoparticles (NPs) with opposite surface charges, namely synthetic layered double hydroxide (LDH) and hectorite (HEC) NPs as adjuvants to promote strong immune responses against the infections. Here both LDH and HEC NPs are showed to be able to carry an appreciable amount of Intimin �� (1.1 and 4.4 mg per mg clay nanomaterials, respectively) and significantly facilitate antigen uptake by antigen-presenting cells. Remarkably, these clay NPs induce strong antibody and cell-mediated immune responses, which are much higher than that by the potent adjuvant, QuilA. Furthermore, these strong immune responses are well maintained for at least four months in the mouse model, during which there are no changes in histopathology of the animal organs. Collectively these data demonstrate the suitability of LDH and HEC NPs as useful adjuvants in new-generation vaccine formulations to control various infectious diseases.

Principles of toxicology applied to nanotechnology: risk assessment

Background: Nanotechnologies are developing very rapidly and nanomaterials (NMs) are increasingly being used in a wide range of applications in science, industry and biomedicine.

Synteza, modyfikacja powierzchni i charakterystyka fizykochemiczna wielofunkcyjnych nanomateria����w luminescencyjnych zawieraj��cych jony pierwiastk��w ziem rzadkich

Wydzia�� Chemii: Zak��ad Ziem Rzadkich

Cyto- and Genotoxicity assessment of manufactured nano cerium dioxide in the A549 cell line

In the past decades the growing application of nanomaterials (NMs) in diverse consumer products has raised various concerns in the field of toxicology. They have been extensively used in a broad range of applications and cover most of the industrial sectors as well as the medicine and the environmental areas. The most common scenarios for human exposure to NMs are occupational, environmental and as consumers and inhalation is the most frequent route of exposure, especially in occupational settings. Cerium dioxide NMs (nano-CeO2) are widely used in a number of applications such as in cosmetics, outdoor paints, wood care products as well as fuel catalysts. For such reason, nano-CeO2 is one of the selected NMs for priority testing within the sponsorship program of the Working Party of Manufactured Nanomaterials of the OECD. In this context, the aim of this study is to assess the safety of nano-CeO2 (NM-212, Joint Research Center Repository) through the characterization of its cytotoxicity and genotoxicity in a human alveolar epithelial cell line. A dispersion of the NM in water plus 0.05% BSA was prepared and sonicated during 16 minutes, according to a standardized protocol. DLS analysis was used to characterize the quality of the NM dispersion in the culture medium. To evaluate the cytotoxicity of nano-CeO2 in the A549 cell line, the colorimetric MTT assay was performed; the capacity of cells to proliferate when exposed to CeO2 was also assessed with the Clonogenic assay. The genotoxicity of this NM was evaluated by the Comet Assay (3 and 24h of exposure) to quantify DNA breaks and the FPG-modified comet assay to assess oxidative DNA damage. The Cytokinesis-Block Micronucleus (CBMN) assay was used to further detect chromosome breaks or loss. The nano-CeO2 particles are spherical, displaying a diameter of 33 nm and 28 m2/g of surface area. The results of the MTT assay did not show any decreased in cells viability following treatment with a dose-range of nano-CeO2 during 24h. Nevertheless, the highest concentrations of this NM were able to significantly reduce the colony forming ability of A549 cells, suggesting that a prolonged exposure may be cytotoxic to these cells. Data from both genotoxicity assays revealed that nano-CeO2 was neither able to induce DNA breaks nor oxidative DNA damage. Likewise, no significant micronucleus induction was observed. Taken together, the present results indicate that this nano-CeO2 is not genotoxic in this alveolar cell line under the tested conditions, although further studies should be performed, e.g., gene mutation in somatic cells and in vivo chromosome damage (rodent micronucleus assay) to ensure its safety to human health.

Efeitos bioqu��micos da exposi����o ao nanomaterial ��xido de grafeno em diferentes tecidos do camar��o branco (Litopenaeus vannamei; Crustacea, Decapoda), atrav��s da suplementa����o na ra����o

O desenvolvimento da nanotecnologia vem se intensificando nos ��ltimos anos. Sendo que os NM j�� est��o sendo utilizados em v��rios produtos dispon��veis no mercado. Dentre os NM mais utilizados est��o os compostos de carbono que embora sejam compostos somente por este elemento podem ter estruturas diferentes que refletem em suas aplica����es e possivelmente em seus efeitos. Dentre os NM de carbono, o grafeno e o ��xido de grafeno apresentam promissoras caracter��sticas que ampliam sua utiliza����o em diversos segmentos desde eletr��nicos at�� a distribui����o de medicamentos. A intensifica����o da produ����o e utiliza����o destes NM �� acompanhada pela libera����o destes nanomateriais no ambiente que pode afetar os organismos vivos, principalmente os animais aqu��ticos. Entretanto, pouco se sabe sobre os efeitos do ��xido de grafeno em crust��ceos de import��ncia comercial como �� o caso do camar��o branco Litopenaeus vannamei. Portanto, a presente disserta����o teve como objetivo avaliar os efeitos biol��gicos da exposi����o ao ��xido de grafeno em diferentes tecidos do camar��o.

Intera����o da cianotoxina microcistina e o nanomaterial de carbono fulereno (C60) em br��nquias do peixe Cyprinus carpio (Teleostei: Cyprinidae) sob incid��ncia de radia����o UVA

A produ����o mundial de nanomateriais tem aumentado nos ��ltimos anos, em fun����o de suas variadas aplica����es tecnol��gicas e, como consequ��ncia do seu crescente uso e demanda, poder��o existir riscos ambientais sendo a ��gua o ambiente onde muitas destas subst��ncias podem exercer efeitos delet��rios. Um dos nanomaterias de carbono mais utilizados �� o fulereno, um composto org��nico lipof��lico que pode se comportar como carreador de mol��culas t��xicas, potencializando a entrada de contaminantes ambientais em ��rg��os espec��ficos, fen��meno conhecido como ���cavalo de Troia���. As microcistinas (MC) s��o cianotoxinas produzidas por cianobact��rias durante epis��dios de flora����o, afetando aos organismos aqu��ticos e ao ser humano. Diversos estudos demonstram que organismos expostos tanto ��s MCs quanto ao fulereno podem causar produ����o excessiva de esp��cies ativas de oxig��nio e alterar os n��veis de antioxidantes. Al��m disso, outro fator que pode vir a intensificar o potencial t��xico de ambos �� a incid��ncia de radia����o UVA. Sendo assim, procurou-se avaliar os efeitos em par��metros de estresse oxidativo da co-exposi����o ex vivo da cianotoxina microcistina-LR (MC-LR) e o nanomaterial de carbono fulereno em br��nquias do peixe Cyprinus carpio sob incid��ncia de radia����o UVA. Os resultados mostraram que: (a) houve uma perda da capacidade antioxidante no tratamento com MC-LR (baixa concentra����o) quando coexposta com fulereno no UVA em rela����o com o tratamento realizado sem co-exposi����o com fulereno; (b) o fulereno no UV diminuiu a atividade da enzima glutationa-Stransferase (GST) quando comparado com o controle no UV; (c) a MC-LR (alta concentra����o) co-exposta com fulereno foi capaz de diminuir as concentra����es do antioxidante glutationa (GSH) quando comparado com o mesmo tratamento tanto no UVA quanto no escuro sem a co-exposi����o ao fulereno; (d) o tratamento MC-LR (baixa concentra����o) com UVA aumentou o dano oxidativo lip��dico quando comparado com o controle UVA; (e) o fulereno n��o causou uma maior bioacumula����o da microcistina no tecido. Sendo assim, pode-se concluir que o fulereno n��o apresentou o potencial de carregador de mol��culas nessas concentra����es de microcistina, por��m, a co-exposi����o dos compostos diminuem tanto capacidade antioxidante total, como a concentra����o da GSH, podendo gerar problemas a longo prazo na detoxifica����o da toxina.

How to design the surface of peptide-loaded nanoparticles for efficient oral bioavailability?

International audience

Are iron oxide nanoparticles safe? Current knowledge and future perspectives

Due to their unique physicochemical properties, including superparamagnetism, iron oxide nanoparticles (ION) have a number of interesting applications, especially in the biomedical field, that make them one of the most fascinating nanomaterials. They are used as contrast agents for magnetic resonance imaging, in targeted drug delivery, and for induced hyperthermia cancer treatments. Together with these valuable uses, concerns regarding the onset of unexpected adverse health effects following exposure have been also raised. Nevertheless, despite the numerous ION purposes being explored, currently available information on their potential toxicity is still scarce and controversial data have been reported. Although ION have traditionally been considered as biocompatible - mainly on the basis of viability tests results - influence of nanoparticle surface coating, size, or dose, and of other experimental factors such as treatment time or cell type, has been demonstrated to be important for ION in vitro toxicity manifestation. In vivo studies have shown distribution of ION to different tissues and organs, including brain after passing the blood-brain barrier; nevertheless results from acute toxicity, genotoxicity, immunotoxicity, neurotoxicity and reproductive toxicity investigations in different animal models do not provide a clear overview on ION safety yet, and epidemiological studies are almost inexistent. Much work has still to be done to fully understand how these nanomaterials interact with cellular systems and what, if any, potential adverse health consequences can derive from ION exposure.

Efeitos t��xicos induzidos pelos nanomateriais Fulereno (C60) e Nanoprata no Poliqueto Laeonereis Acuta (Nereididae) e nas comunidades bacterianas que habitam sua superf��cie corporal

O fulereno (C60) pertence a uma fam��lia de nanomateriais (NM) constitu��da exclusivamente de ��tomos de carbono, sendo encontrado na forma de suspens��o na ��gua (nC60). A nanoprata (nAg) possui um excepcional e amplo espectro bactericida e um custo de fabrica����o relativamente baixo. No entanto, pouco se sabe a respeito dos eventuais efeitos t��xicos induzidos por estes NM em organismos estuarinos. O poliqueto Laeonereis acuta tem o muco colonizado por comunidades bacterianas. H�� registros de que L. acuta apresenta um gradiente corporal para concentra����o de EAO e capacidade antioxidante total. Neste estudo, os poliquetos foram expostos in vivo durante 24 horas ao nC60 e �� nAg, separadamente. Ap��s isso, as unidades formadoras de col��nias (UFC) bacterianas foram contadas e pesadas, al��m de serem realizadas diversas medi����es bioqu��micas nos poliquetos e nas bact��rias. Os n��meros de UFC bacterianas expostas ao nC60 foi menor na concentra����o de 0.01mg/L e os n��meros de UFC bacterianas expostas �� nAg foram similares aos dados de biomassa, diminuindo na maior concentra����o (1.0 mg/L) (p<0.05). A capacidade antioxidante contra radicais peroxil em homogeneizados bacterianos expostos ao nC60 foi menor na concentra����o de 0.1mg/L quando comparado ao controle (p<0.05). A regi��o anterior apresentou menor capacidade antioxidante (p<0.05) nos poliquetos expostos a 1.0 mg/L, quando comparado ao controle. Os poliquetos expostos �� nAg apresentaram menor capacidade antioxidante na regi��o posterior na concentra����o de 1.0 mg/L quando comparado ao controle (p<0.05). O conte��do de per��xidos lip��dicos (TBARS) foi reduzido na regi��o anterior dos poliquetos expostos nas duas menores concentra����es ( 0.01 e 0.1 mg/L) de nC60 (p<0.05). Na regi��o corporal posterior, somente os organismos expostos a maior concentra����o de nC60 (1.0 mg/L) mostraram aumento na concentra����o de TBARS quando comparado ao grupo controle (p<0.05). A atividade da enzima glutationa-Stransferase (GST) foi aumentada (p<0.05) na regi��o m��dia e posterior dos poliquetos expostos a 0.1 mg/L de nC60. Como conclus��es pode se dizer que os dois NM induziram efeitos t��xicos ainda numa situa����o (escurid��o) onde o fulereno n��o �� fotoexcitado. O aumento na produ����o e comercializa����o de produtos com NM levanta a quest��o dos riscos ambientais associados ao desenvolvimento da nanotecnologia.

Influ��ncia dos ��cidos graxos do tipo ��mega-3 ou ��mega-6 e o nanomaterial de carbono fulereno (C60) no estado antioxidante em suspens��es celulares de c��rebro de Cyprinus carpio (Pisces, Cyprinidae)

Os nanomateriais de carbono como o fulereno (C60) apresenta comportamentos bioqu��micos distintos, podendo atuar como antioxidante ou pr��-oxidante em diferentes sistemas biol��gicos. Outra evid��ncia ao C60 refere-se a sua caracter��stica lipofilica, na qual oferece a����o mais direta a diferentes tipos de membranas celulares. Do mesmo modo ��cidos graxos poliinsaturados (AGPs) como o ��mega-3 (DHA) e o ��mega-6 (LA) s��o importantes para fun����es celulares da membrana, sendo considerados antioxidantes cl��ssicos. Dessa forma este estudo avaliou em suspens��es celulares de c��rebro da carpa (Cyprinus carpio, Cyprinidae), o efeito de C60 ap��s um pr��-tratamento com DHA ou LA. Para tal avalia����o os ensaios consistiram em um pr��-tratamento com AGPs (48h) e ap��s exposi����o a C60 (2h). Como resultados observamos que a viabilidade celular e a capacidade antioxidante total n��o apresentaram diferen��a (p> 0.05) entre todos os grupos. Em rela����o a valores de esp��cies ativas de oxig��nio e dano lip��dico foi observado redu����o nos seus valores nos grupos expostos ao C60 pr�� ��� tratados com AGPs (p<0.05). Em termos de ciste��na, ocorre uma redu����o da sua concentra����o em todos os grupos expostos ao C60. Por��m para glutationa a exposi����o ao C60 provoca um aumento de sua concentra����o nos grupo controle (sem AGPs) e no grupo pr�� ��� tratado com DHA. Dessa forma consideramos que o pr�� ��� tratamento com AGPs �� ben��fico ��s c��lulas, uma vez que um aumento nos n��veis de glutationa e uma diminui����o na concentra����o de esp��cies ativas de oxig��nio e peroxida����o lip��dica foram observados nos grupos expostos ao C60. Sendo assim um bom estado nutritivo em termos da concentra����o de AGPs foi considerado ben��fico na exposi����o ao fulereno.

Chemical and physical effects of ultrasound: sonoluminescence and materials

When a liquid is irradiated with ultrasound, acoustic cavitation (the formation, growth, and implosive collapse of bubbles in liquids irradiated with ultrasound) generally occurs. This is the phenomenon responsible for the driving of chemical reactions (sonochemistry) and the emission of light (sonoluminescence). The implosive collapse of bubbles in liquids results in an enormous concentration of sound energy into compressional heating of the bubble contents. Therefore, extreme chemical and physical conditions are generated during cavitation. The study of multibubble sonoluminescence (MBSL) and single-bubble sonoluminescence (SBSL) in exotic liquids such as sulfuric acid (H2SO4) and phosphoric acid (H3PO4) leads to useful information regarding the intracavity conditions during bubble collapse. Distinct sonoluminescing bubble populations were observed from the intense orange and blue-white emissions by doping H2SO4 and H3PO4 with sodium salts, which provides the first experimental evidence for the injected droplet model over the heated-shell model for cavitation. Effective emission temperatures measured based on excited OH��� and PO��� emission indicate that there is a temperature inhomogeneity during MBSL in 85% H3PO4. The formation of a temperature inhomogeneity is due to the existence of different cavitating bubble populations: asymmetric collapsing bubbles contain liquid droplets and spherical collapsing bubbles do not contain liquid droplets. Strong molecular emission from SBSL in 65% H3PO4 have been obtained and used as a spectroscopic probe to determine the cavitation temperatures. It is found that the intracavity temperatures are dependent on the applied acoustic pressures and the thermal conductivities of the dissolved noble gases. The chemical and physical effects of ultrasound can be used for materials synthesis. Highly reactive species, including HO2���, H���, and OH��� (or R��� after additives react with OH���), are formed during aqueous sonolysis as a consequence of the chemical effects of ultrasound. Reductive species can be applied to synthesis of water-soluble fluorescent silver nanoclusters in the presence of a suitable stabilizer or capping agent. The optical and fluorescent properties of the Ag nanoclusters can be easily controlled by the synthetic conditions such as the sonication time, the stoichiometry of the carboxylate groups to Ag+, and the polymer molecular weight. The chemical and physical effects of ultrasound can be combined to prepare polymer functionalized graphenes from graphites and a reactive solvent, styrene. The physical effects of ultrasound are used to exfoliate graphites to graphenes while the chemical effects of ultrasound are used to induce the polymerization of styrene which can then functionalize graphene sheets via radical coupling. The prepared polymer functionalized graphenes are highly stable in common organic solvents like THF, CHCl3, and DMF. Ultrasonic spray pyrolysis (USP) is used to prepare porous carbon spheres using energetic alkali propiolates as the carbon precursors. In this synthesis, metal salts are generated in situ, introducing porous structures into the carbon spheres. When different alkali salts or their mixtures are used as the precursor, carbon spheres with different morphologies and structures are obtained. The different precursor decomposition pathways are responsible for the observed structural difference. Such prepared carbon materials have high surface area and are thermally stable, making them potentially useful for catalytic supports, adsorbents, or for other applications by integrating other functional materials into their pores.

Evaluation of the cytotoxic and genotoxic effects of benchmark multi-walled carbon nanotubes in relation to their physicochemical properties

To contribute with scientific evidence to the grouping strategy for the safety assessment of multi-walled carbon nanotubes (MWCNTs), this work describes the investigation of the cytotoxic and genotoxic effects of four benchmark MWCNTs in relation to their physicochemical characteristics, using two types of human respiratory cells. The cytotoxic effects were analysed using the clonogenic assay and replication index determination. A 48h-exposure of cells revealed that NM-401 was the only cytotoxic MWCNT in both cell lines, but after 8-days exposure, the clonogenic assay in A549 cells showed cytotoxic effects for all the tested MWCNTs. Correlation analysis suggested an association between the MWCNTs size in cell culture medium and cytotoxicity. No induction of DNA damage was observed after any MWCNTs in any cell line by the comet assay, while the micronucleus assay revealed that both NM-401 and NM-402 were genotoxic in A549 cells. NM-401 and NM-402 are the two longest MWCNTs analyzed in this work, suggesting that length may be determinant for genotoxicity. No induction of micronuclei was observed in Beas-2B cell line and the different effect in both cell lines is explained in view of the size-distribution of MWCNTs in the cell culture medium, rather than cell's specificities.

Niosomes as Nanoparticular Drug Carriers: Fundamentals and Recent Applications

Drug delivery systems are defined as formulations aiming for transportation of a drug to the desired area of action within the body. The basic component of drug delivery systems is an appropriate carrier that protects the drug from rapid degradation or clearance and thereby enhances drug concentration in target tissues. Based on their biodegradable, biocompatible, and nonimmunogenic structure, niosomes are promising drug carriers that are formed by self-association of nonionic surfactants and cholesterol in an aqueous phase. In recent years, numerous research articles have been published in scientific journals reporting the potential of niosomes to serve as a carrier for the delivery of different types of drugs. The present review describes preparation methods, characterization techniques, and recent studies on niosomal drug delivery systems and also gives up to date information regarding recent applications of niosomes in drug delivery.

Investigations of the Toxic Effect of Silver Nanoparticles on Mammalian Cell Lines

Silver nanoparticles are widely used for many applications. In this study silver nanoparticles have been tested for their toxic effect on fibroblasts (NIH-3T3), on a human lung adenocarcinoma epithelial cell line (A-549), on PC-12-cells, a rat adrenal pheochromocytoma cell line, and on HEP-G2-cells, a human hepatocellular carcinoma cell line. The viability of the cells cultivated with different concentrations of silver was determined by the MTT assay, a photometric method to determine cell metabolism. Dose-response curves were extrapolated and IC50, total lethal concentration (TLC), and no observable adverse effect concentration (NOAEC) values were calculated for each cell line. As another approach, ECIS (electric-cell-substrate-impedance-sensing) an automated method to monitor cellular behavior in real-time was applied to observe cells cultivated with silver nanoparticles. To identify the type of cell death the membrane integrity was analyzed by measurements of the lactate dehydrogenase releases and by determination of the caspase 3/7 activity. To ensure that the cytotoxic effect of silver nanoparticles is not traced back to the presence of Ag+ ions in the suspension, an Ag+ salt (AgNO3) has been examined at the same concentration of Ag+ present in the silver nanoparticle suspension that is assuming that the Ag particles are completely available as Ag+ ions.