Synthesis of KNbO3 nanostructures by a microwave assisted hydrothermal method

One-dimensional nanostructures of KNbO3 have attracted a great interest in the scientific community, mainly because of their promising application as nanoelectromechanical systems (NEMS). However, the synthesis of KNbO3 structures becomes complex due to the natural tendency to form non-stoichiometric potassium niobates. In this context, we report on the crystallization of one-dimensional KNbO3 nanostructures through the reaction between Nb2O5 and KOH under microwave-assisted hydrothermal synthesis (M-H). The use of this synthesis method made possible a very fast synthesis of singlecrystalline powders. Based on SEM, TEM and XRD characterizations, the influence of the synthesis time and the reactants concentration in the structure and morphology of the resultant KNbO3 was established. The conditions that favor the crystallization of nanofingers were determined to be small amounts of Nb2O5 and short reaction times.Fil: Paula, Amauri J.. Universidade de Sao Paulo; BrasilFil: Parra, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Zaghete, Maria A.. Universidade de Sao Paulo; BrasilFil: Varela, José A.. Universidade de Sao Paulo; Brasi

Study on the K3Li2Nb5O15 formation during the production of (Na0.5K0.5)((1-x))LixNbO3 lead-free piezoceramics at the morphotropic phase boundary

Because of the environmental concerns, the manufacture of ceramics based on lead titanate zirconate [Pb(Zr1-xTix)O-3 - PZT] has been condemned because of the lead toxicity. In this context, the electromechanical properties of sodium, potassium and lithium niobate [(Na-0.5-x/2K0.5-x/2Lix)NbO3 - NKLN] at the morphotropic phase boundary granted these materials the position of most suitable candidate to replace PZT. However, the production of these ceramics is rather critical mainly because of a natural tendency of forming secondary phases. To help with the studies of the synthesis of this lead-free piezoceramic, this work presents an evaluation of the crystallization of the (Na0.47K0.47Li0.06)NbO3 phase by solid-state reactions. TG-DTA, XRD, dilatometric and ferroelectric hysteresis analyses indicated that a secondary phase (K3Li2Nb5O15) crystallizes at temperatures above 850 degrees C and also during the sintering of the powders compacts at 1080 degrees C. To prevent the formation of this phase, the addition of Na2Nb2O6 center dot nH(2)O microfibers obtained through a microwave hydrothermal synthesis was performed in the sintering process. After to this addition, the suppression of the K3Li2Nb5O15 phase occurred and an increase of the NKLN electrical properties was then obtained. (C) 2009 Elsevier Ltd. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Microwave-assisted hydrothermal synthesis of structurally and morphologically controlled sodium niobates by using niobic acid as a precursor

There are many advantages to using a microwave as a source of heat in hydrothermal reactions. Because it is a quick and homogeneous way to crystallize ceramic powders, it was used in this work for the production of antiferroelectric sodium mobate (NaNbO3) in a cubic-like form and its intermediary phase, disodium diniobate hydrate (Na2Nb2O6 center dot H2O), with a fiber morphology. The syntheses were carried out by treating niobic acid (Nb2O5 center dot nH(2)O) with NaOH. By changing the reaction time and the concentration of the reactants, particles with different structures and different morphologies could be obtained. The structural evolution of the products of this reaction was elucidated on the basis of the arrangement of the NbO6 octahedral units. Conclusive results were obtained with morphological and structural characterizations through XRD, TEM, MEV, and NMR and Raman spectroscopy. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Immunomodulatory effects of transforming growth factor-β in the liver

Graphene and its derivatives are promising candidates for important biomedical applications because of their versatility. The prospective use of graphene-based materials in a biological context requires a detailed comprehension of the toxicity of these materials. Moreover, due to the expanding applications of nanotechnology, human and environmental exposures to graphene-based nanomaterials are likely to increase in the future. Because of the potential risk factors associated with the manufacture and use of graphene-related materials, the number of nanotoxicological studies of these compounds has been increasing rapidly in the past decade. These studies have researched the effects of the nanostructural/biological interactions on different organizational levels of the living system, from biomolecules to animals. This review discusses recent results based on in vitro and in vivo cytotoxicity and genotoxicity studies of graphene-related materials and critically examines the methodologies employed to evaluate their toxicities. The environmental impact from the manipulation and application of graphene materials is also reported and discussed. Finally, this review presents mechanistic aspects of graphene toxicity in biological systems. More detailed studies aiming to investigate the toxicity of graphene-based materials and to properly associate the biological phenomenon with their chemical, structural, and morphological variations that result from several synthetic and processing possibilities are needed. Knowledge about graphene-based materials could ensure the safe application of this versatile material. Consequently, the focus of this review is to provide a source of inspiration for new nanotoxicological approaches for graphene-based materials. © 2014 American Chemical Society.Graphene and its derivatives are promising candidates for important biomedical applications because of their versatility. The prospective use of graphene-based materials in a biological context requires a detailed comprehension of the toxicity of these ma272159168FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOsem informaçãosem informaçãoNovoselov, K.S., Geim, A.K., Morozov, S.V., Jiang, D., Zhang, Y., Dubonos, S.V., Grigorieva, I.V., Firsov, A.A., Electric field effect in atomically thin carbon films (2004) Science, 306, pp. 666-669Sanchez, V.C., Jackhak, A., Hurt, R.H., Kane, A.B., Biological interactions of graphene-family nanomaterials: An interdisciplinary review (2012) Chem. Res. Toxicol., 25, pp. 15-34Bussy, C., Ali-Boucetta, H., Kostarelos, K., Safety considerations for graphene: Lessons learnt from carbon nanotubes (2013) Acc. Chem. Res., 46, pp. 692-701Shih, C.J., Lin, S., Sharma, R., Strano, M.S., Blankschtein, D., Understanding the pH-dependent behavior of graphene oxide aqueous solutions: A comparative experimental and molecular dynamics simulation study (2012) Langmuir, 28, pp. 235-241Bitounis, D., Ali-Boucetta, H., Hong, B.H., Min, D.-H., Kostarelos, K., Prospects and challenges of graphene in biomedical applications (2013) Adv. Mater., 25, pp. 2258-2268Sreeprasad, T.S., Pradeep, T., Graphene for environmental and biological applications (2012) Int. J. Mod. Phys. B, 26, pp. 1242001-1242026Kuila, T., Bose, S., Khanra, P., Mishra, A.K., Kim, N.H., Lee, J.H., Recent advances in graphene-based biosensors (2011) Biosens. Bioelect., 26, pp. 4637-4648Shen, H., Zhang, L., Liu, M., Zhang, Z., Biomedical applications of graphene (2012) Theranostics, 2, pp. 283-294Liu, J., Tang, J., Gooding, J.J., Strategies for chemical modification of graphene and applications of chemically modified graphene (2012) J. Mater. Chem., 22, pp. 12435-12452Bao, H., Pan, Y., Li, L., Recent advances in graphene-based nanomaterials for biomedical applications (2012) Nano Life, 2, pp. 1230001-1230015Fisher, C., Rider, A.E., Kumar, S., Levchenko, I., Han, Z., Ostrikov, K., Applications and nanotoxicity of carbon nanotubes and graphene in biomedicine (2012) J. Nanomat., , DOI: 10.1155/2012/315185Koyakutty, M., Sasidharan, A., Nair, S., Biomedical Applications of Graphene: Opportunities and Challenges (2012) Graphene: Synthesis, Properties, and Phenomena, , (Rao, C. N. R. and Sood, A. K. Eds.) Chapter 2, Wiley-VCH, Weinheim, GermanyKotchey, G.P., Allen, B.L., Vedala, H., Yanamala, N., Kapralov, A.A., Tyurina, Y.T., Klein-Seetharaman, J., Star, A., The enzymatic oxidation of graphene oxide (2011) ACS Nano, 5, pp. 2098-2108Kuila, T., Bose, S., Khanra, P., Mishra, A.K., Kim, N.H., Lee, J.H., A green approach for the reduction of graphene oxide by wild carrot root (2012) Carbon, 9, pp. 914-921Zhang, Y., Wu, C., Guo, S., Zhang, J., Interactions of graphene and graphene oxide with proteins and peptides (2013) Nanotechnol. Rev., 2, pp. 27-45Girish, C.M., Sasidharan, A., Gowd, G.S., Nair, S., Koyakutty, M., Confocal Raman imaging study showing macrophage mediated biodegradation of graphene in vivo (2013) Adv. Healthcare Mater., , DOI: 10.1002/adhm.201200489Liu, S., Zeng, T.H., Hofmann, M., Burcombe, E., Wei, J., Jiang, R., Kong, J., Chen, Y., Antibacterial activity of graphite, graphite oxide, graphene oxide, and reduced graphene oxide: Membrane and oxidative stress (2011) ACS Nano, 5, pp. 6971-6980Jastrzebska, A.M., Kurtycz, P., Olszyna, A.R., Recent advances in graphene family materials toxicity investigations (2012) J. Nanopart. Res., 14, pp. 1320-1321Bianco, A., Graphene: Safe or toxic? the two faces of the medal (2013) Angew. Chem., Int. Ed., 52, pp. 4986-4997Ali-Boucetta, H., Bitounis, D., Raveendran-Nair, R., Servant, A., Van Den Bossche, J., Kostarelos, K., Purified graphene oxide dispersions lack in vitro cytotoxicity and in vivo pathogenicity (2013) Adv. Healthcare Mater., 2, pp. 443-441Ali-Boucetta, H., Bitounis, D., Raveendran-Nair, R., Servant, A., Van Den Bossche, J., Kostarelos, K., Graphene oxide: Purified graphene oxide dispersions lack in vitro cytotoxicity and in vivo pathogenicity (2013) Adv. Healthcare Mater., 2, pp. 512-512Agarwal, S., Zhou, X., Ye, F., He, Q., Chen, G.C.K., Soo, J., Boey, F., Chen, P., Interfacing live cells with nanocarbon substrates (2010) Langmuir, 26, pp. 2244-2247Vallabani, N.V.S., Mittal, S., Shukla, R.K., Pandey, A.K., Dhakate, S.R., Pasricha, R., Dhawan, A., Toxicity of graphene in normal human lung cells (BEAS-2B) (2011) J. Biomed. Nanotechnol., 7, pp. 106-107Zhang, Y., Ali, S.F., Dervishi, E., Xu, Y., Li, Z., Casciano, D., Biris, A.S., Cytotoxicity effects of graphene and single-wall carbon nanotubes in neural phaeochromocytoma-derived PC12 cells (2010) ACS Nano, 4, pp. 3181-3186Zhang, L., Xia, J., Zhao, Q., Liu, L., Zhang, Z., Functional graphene oxide as a nanocarrier for controlled loading and targeted delivery of mixed anticancer drugs (2010) Small, 6, pp. 537-544Singh, S.K., Singh, M.K., Nayak, M.K., Kumari, S., Shrivastava, S., Gracio, J.J.A., Dash, D., Thrombus inducing property of atomically thin graphene oxide sheets (2011) ACS Nano, 5, pp. 4987-4996Duch, M.C., Budinger, G.R.S., Liang, Y.T., Soberanes, S., Urich, D., Chiarella, S.E., Campochiaro, L.A., Mutlu, G.M., Minimizing oxidation and stable nanoscale dispersion improves the biocompatibility of graphene in the lung (2011) Nano Lett., 11, pp. 5201-5207Yuan, J., Gao, H., Ching, C.B., Comparative protein profile of human hepatoma HepG2 cells treated with graphene and single-walled carbon nanotubes: An iTRAQ-coupled 2D LC-MS/MS proteome analysis (2011) Toxicol. Lett., 207, pp. 213-221Yuan, J., Gao, H., Sui, J., Duan, H., Chen, W.N., Ching, C.B., Cytotoxicity evaluation of oxidized single-walled carbon nanotubes and graphene oxide on human hepatoma HepG2 cells: An iTRAQ-coupled 2D LC-MS/MS proteome analysis (2012) Toxicol. Sci., 126, pp. 149-161Yan, Y., Zhao, F., Li, S., Hu, Z., Zhao, Y., Low-toxic and safe nanomaterials by surface-chemical design, carbono nanotubes, fullerenes, metallofullerenes, and graphenes (2011) Nanoscale, 3, pp. 362-382Yang, K., Wan, J., Zhang, S., Zhang, Y., Lee, S.T., Liu, Z., In vivo pharmacokinetics, long-term biodistribution, and toxicology of PEGylated graphene in mice (2011) ACS Nano, 5, pp. 516-522Schinwald, A., Murphy, F.A., Jones, A., Macnee, W., Donaldson, K., Graphene-based nanoplatelets: A new risk to the respiratory system as a consequence of their unusual aerodynamic properties (2012) ACS Nano, 6, pp. 736-746Sun, X., Liu, Z., Welsher, K., Robinson, J.T., Goodwin, A., Zaric, S., Dai, H., Nano-graphene oxide for cellular imaging and drug delivery (2008) Nano Res., 1, pp. 203-212Liu, Z., Robinson, J.T., Sun, X.M., Dai, H., PEGylated nanographene oxide for delivery of water-insoluble cancer drugs (2008) J. Am. Chem. Soc., 130, pp. 10876-10877Feng, L., Liu, Z., Graphene in biomedicine: Opportunities and challenges (2011) Nanomedicine, 6, pp. 317-324Robinson, J.T., Tabakman, S.M., Liang, Y., Wang, H., Casalongue, H.S., Vinh, D., Dai, H., Ultrasmall reduced graphene oxide with high near-infrared absorbance for photothermal therapy (2011) J. Am. Chem. Soc., 133, pp. 6825-6831Chang, Y., Yang, S.T., Liu, J.H., Dong, E., Wang, Y., Cao, A., Liu, Y., Wang, H., In vitro toxicity evaluation of graphene oxide on A549 cells (2011) Toxicol. Lett., 200, pp. 201-210Akhavan, O., Ghaderi, E., Akhavan, A., Size-dependent genotoxicity of graphene nanoplatelets in human stem cells (2012) Biomaterials, 33, pp. 8017-8025Matesanz, M.C., Vila, M., Feito, M.J., Linares, J., Gonçalves, G., Vallet-Regi, M., Marques, P.A.A.P., Portolés, M.T., The effects of graphene oxide nanosheets localized on F-actin filaments on cell-cycle alterations (2013) Biomaterials, 34, pp. 1562-1569Yue, H., Wei, W., Yue, Z., Wang, B., Luo, N., Gao, Y., Ma, D., Su, Z., The role of the lateral dimension of graphene oxide in the regulation of cellular responses (2012) Biomaterials, 33, pp. 4013-4021Stefani, S., Paula, A.L., Vaz, B.G., Silva, R.A., Andrade, N.F., Souza Filho, A.G., Justo, G.Z., Alves, O.L., Structural and proactive safety aspects of oxidation debris from multiwalled carbon nanotubes (2011) J. Hazard. Mater., 189, pp. 391-396Umbuzeiro, G.A., Coluci, V.R., Honório, J., Giro, R., Morales, D.A., Lage, A.S., Mazzei, J.L., Alves, O.L., Understanding the interaction of multiwalled carbon nanotubes with mutagenic organic pollutants using computation modeling and biological experiments (2011) Trends Anal. Chem., 30, pp. 437-446Andrade, N.F., Martinez, D.S.T., Paula, A.J., Silveira, J.V., Alves, O.L., Souza Filho, A.G., Temperature effects on the nitric acid oxidation of industrial grade multiwalled carbon nanotubes (2013) J. Nanopart. Res., 15, pp. 1761-1768Mu, Q., Su, G., Li, L., Gilbertson, B.O., Yu, L.H., Zhang, Q., Sun, Y.P., Yan, B., Size-dependent cell uptake of protein-coated graphene oxide nanosheets (2012) ACS Appl. Mater. Interfaces, 4, pp. 2259-2266Li, Y., Liu, Y., Fu, Y., Wei, T., Guyader, L.L., Gao, G., Liu, R.S., Chen, C., The triggering of apoptosis in macrophages by pristine graphene through the MAPK and TGF-beta signaling pathways (2012) Biomaterials, 33, pp. 402-411Wang, K., Ruan, J., Song, H., Zhang, J., Wo, Y., Guo, S., Cui, D., Biocompatibility of graphene oxide (2011) Nanoscale Res. Lett., 6, pp. 1-8Li, Y., Liu, Y., Fu, Y., Wei, T.T., Le Guyader, L., Gao, G., Liu, R.S., Chen, C.Y., The triggering of apoptosis in macrophages by pristine graphene through the MAPK and TGF-beta signaling pathways (2012) Biomaterials, 33, pp. 402-411Chen, G.Y., Yang, H.J., Lu, C.H., Chao, Y.C., Hwang, S.M., Chen, C.L., Lo, K.W., Hu, Y.C., Simultaneous induction of autophagy and toll-like receptor signaling pathways by graphene oxide (2012) Biomaterials, 33, pp. 6559-6569Tkach, A.V., Yanamala, N., Stanley, S., Shurin, M.R., Shurin, G.V., Kisin, E.R., Murray, A.R., Shvedova, A.A., Graphene oxide, but not fullerenes, targets immunoproteasomes and suppresses antigen presentation by dendritic cells (2013) Small, 9, pp. 1686-9160Liao, K.H., Lin, Y.S., Macosko, C.W., Haynes, C.L., Cytotoxicity of graphene oxide and graphene in human erythrocytes and skin fibroblasts (2011) ACS Appl. Mater. Interfaces, 3, pp. 2607-2615Gurunathan, S., Han, J.W., Eppakayala, V., Kim, J.H., Green synthesis of graphene and its cytotoxic effects in human breast cancer cells (2013) Int. J. Nanomed., 8, pp. 1015-1027Ruiz, O.N., Fernando, K.A., Wang, B., Brown, N.A., Luo, P.G., McNamara, N.D., Vangsness, M., Bunker, C.E., Graphene oxide: A nonspecific enhancer of cellular growth (2011) ACS Nano, 5, pp. 8100-8107Akhavan, O., Ghaderi, E., Aghayee, S., Fereydooni, Y., Talebi, A., The use of a glucose-reduced graphene oxide suspension for photothermal cancer therapy (2012) J. Mater. Chem., 22, pp. 13773-13781Cheng, C., Nie, S., Li, S., Peng, H., Yang, H., Ma, L., Sun, S., Zhao, C., Biopolymer functionalized reduced graphene oxide with enhanced biocompatibility via mussel inspired coatings/anchors (2013) J. Mater. Chem. B, 1, pp. 265-275Jaworski, S., Sawosz, E., Grodzik, M., Winnicka, A., Prasek, M., Wierzbicki, M., Chwalibog, A., In vitro evaluation of the effects of graphene platelets on glioblastoma multiforme cells (2013) Int. J. Nanomed., 8, pp. 413-420Sasidharan, A., Panchakarla, L.S., Sadanandan, A.R., Ashokan, A., Chandran, P., Girish, C.M., Menon, D., Koyakutty, M., Hemocompatibility and macrophage response of pristine and functionalized graphene (2012) Small, 8, pp. 1251-1263Singh, S.K., Singh, M.K., Kulkarni, P.P., Sonkar, V.K., Grácio, J.J.A., Dash, D., Amine-modified graphene: Thrombo-protective safer alternative to graphene oxide for biomedical applications (2012) ACS Nano, 6, pp. 2731-2740Agemy, L., Sugahara, K.N., Kotamraju, V.R., Gujraty, K., Girard, O.M., Kono, Y., Mattrey, R.F., Ruoslahti, E., Nanoparticle-induced vascular blockade in human prostate cancer (2010) Blood, 116, pp. 2847-2856Qiao, Y., An, J., Ma, L., Single cell array based assay for in vitro genotoxicity study of nanomaterials (2013) Anal. Chem., 85, pp. 4107-4112Zhang, S., Yang, K., Feng, L., Liu, C., In vitro and in vivo behaviors of dextran functionalized graphene (2011) Carbon, 49, pp. 4040-4049Fako, V.E., Furgeson, D.Y., Zebrafish as a correlative and predictive model for assessing biomaterial nanotoxicity (2009) Adv. Drug Delivery Rev., 61, pp. 478-486Gollavelli, G., Ling, Y.C., Multi-functional graphene as an in vitro and in vivo imaging probe (2012) Biomaterials, 33, pp. 2532-2545Liu, C.-W., Xiong, F., Jia, H.-Z., Wang, X.-L., Cheng, H., Sun, Y.-H., Zhang, X.-Z., Feng, J., Graphene-based anticancer nanosystem and its biosafety evaluation using a zebrafish model (2013) Biomacromolecules, 14, pp. 358-366Yang, K., Zhang, S., Zhang, G., Sun, X., Lee, S.T., Liu, Z., Graphene in mice: Ultrahigh in vivo tumor uptake and efficient photothermal therapy (2010) Nano Lett., 10, pp. 3318-3323Sahu, A., Choi, W.I., Tae, G., A stimuli-sensitive injectable graphene oxide composite hydrogel (2012) Chem. Commun., 48, pp. 5820-5822Yang, K., Gong, H., Shi, X., Wan, J., Zhang, Y., Liu, Z., In vivo biodistribution and toxicology of functionalized nano-graphene oxide in mice after oral and intraperitoneal administration (2013) Biomaterials, 34, pp. 2787-2795Zanni, E., De Bellis, G., Bracciale, M.P., Broggi, A., Santarelli, M.L., Sarto, M.S., Palleschi, C., Uccelletti, D., Graphite nanoplatelets and Caenorhabditis elegans: Insights from an in vivo model (2012) Nano Lett., 12, pp. 2740-2744Akhavan, O., Ghaderi, E., Toxicity of graphene and graphene oxide nanowalls against bacteria (2010) ACS Nano, 4, pp. 5731-5736Sasidharan, A., Panchakarla, L.S., Chandran, P., Menon, D., Nair, S., Rao, C.N.R., Koyakutty, M., Differential nano-bio interactions and toxicity effects of pristine versus functionalized graphene (2011) Nanoscale, 3, pp. 2461-2464Zhang, X., Yin, J., Peng, C., Hu, W., Zhu, Z., Li, W., Fan, C., Huang, Q., Distribution and biocompatibility studies of graphene oxide in mice after intravenous administration (2011) Carbon, 49, pp. 986-995Yan, L., Wang, Y., Xu, X., Zeng, C., Hou, J., Lin, M., Xu, J., Liu, Y., Can graphene oxide cause damage to eyesight? (2012) Chem. Res. Toxicol., 25, pp. 1265-1270Bonaccorso, F., Ferrari, A., Falko, V., Novoselov, K., Scientific and Technological Roadmap for Graphene in ICT (2012) Graphene-CA D3.1, pp. 1-178. , Project funded by the European Commission under grant agreement n 284558Hu, W., Peng, C., Luo, W., Lv, M., Li, X., Li, D., Huang, Q., Fan, C., Graphene-based antibacterial paper (2010) ACS Nano, 4, pp. 4317-4323Cai, X., Lin, M., Tan, S., Mai, W., Zhang, Y., Liang, Z., Lin, Z., Zhang, X., The use of polyethyleneimine-modified reduced graphene oxide as a substrate for silver nanoparticles to produce a material with lower cytotoxicity and long-term antibacterial activity (2012) Carbon, 50, pp. 3407-3415Wang, G., Qian, F., Saltikov, C.W., Jiao, Y., Li, Y., Microbial reduction of graphene oxide by Shewanella (2011) Nano Res., 6, pp. 563-570Liu, S., Hu, M., Zeng, T.H., Wu, R., Jiang, R., Wei, J., Wang, L., Chen, Y., Lateral Dimension-dependent antibacterial activity of graphene oxide sheets (2012) Langmuir, 28, pp. 12364-12372Carpio, I.E.M., Santos, C.M., Wei, X., Rodrigues, D.F., Toxicity of a polymer-graphene oxide composite against bacterial planktonic cells, biofilms, and mammalian cells (2012) Nanoscale, 4, pp. 4746-4756Santos, C.M., Mangadlao, J., Ahmed, F., Leon, A., Advincula, R.C., Rodrigues, D.F., Graphene nanocomposite for biomedical applications: Fabrication, antimicrobial and cytotoxic investigations (2012) Nanotechnology, 23, p. 395101Akhavan, O., Ghaderi, E., Escherichia coli bacteria reduce graphene oxide to bactericidal graphene in a self-limiting manner (2012) Carbon, 50, pp. 1853-1860Bykkam, S., Rao, K.V., Chakra, C.H.S., Thunugunta, T., Synthesis and characterization of graphene oxide and its antimicrobial activity against Klebsiella and Staphylococus (2013) Int. J. Adv. Biotechnol. Res., 4, pp. 142-146Krishnamoorthy, K., Umasuthan, N., Mohan, R., Lee, J., Kim, S.J., Activity of graphene oxide nanosheets (2012) Sci. Adv. Mater., 4, pp. 1111-1117Chen, J., Wang, X., Han, H., A new function of graphene oxide emerges: Inactivating phytopathogenic bacterium Xanthomonas oryzae pv. Oryzae (2013) J. Nanopart. Res., 15, pp. 1658-1671Zhao, J., Deng, B., Lv, M., Li, J., Zhang, Y., Jiang, H., Peng, C., Fan, C., Graphene oxide-based antibacterial cotton fabrics (2013) Adv. Healthcare Mater., 2, pp. 1259-1266Sawangphruk, M., Srimuk, P., Chiochan, P., Sngsri, T., Siwayaprahm, P., Synthesis and antifungal activity of reduced graphene oxide nanosheets (2012) Carbon, 50, pp. 5156-5161Kemp, K.C., Saema, H., Saleh, M., Le, N.H., Mahesh, K., Chandra, V., Kim, K.S., Environmental applications using graphene composites: Water remediation and gas adsorption (2013) Nanoscale, 5, pp. 3149-3171Begum, P., Ikhtiari, R.I., Fugetsu, B., Graphene phytotoxicity in the seedling stage of cabbage, tomato, red spinach, and lettuce (2011) Carbon, 49, pp. 3907-3919Khodakovskaya, M.V., De Silva, K., Nedosekin, D.A., Dervishi, E., Biris, A.S., Shashkov, E.V., Galanzha, E.I., Zharov, V.P., Complex genetic, photothermal, and photoacoustic analysis of nanoparticle-plant interactions (2011) Proc. Natl. Acad. Sci. U.S.A., 108, pp. 1028-1033Ahmed, F., Rodrigues, D.F., Investigation of acute effects of graphene oxide on wastewater microbial community: A case study (2013) J. Hazard. Mater., 256-257, pp. 33-39Gurunathan, S., Han, J.W., Eppakayala, V., Kim, J.H., Biocompatibility of microbially reduced graphene oxide in primary mouse embryonic fibroblast cells (2013) Colloids Surf., B, 105, pp. 58-66Gurunathan, S., Han, J.W., Dayem, A.A., Eppakayala, V., Kim, J.H., Oxidative stress-mediated antibacterial activity of graphene oxide and reduced graphene oxide in Pseudomonas aeruginosa (2012) Int. J. Nanomed., 7, pp. 5901-5914Wojtoniszak, M., Chen, X., Kalenczuk, R.J., Wajda, A., Lapczuk, J., Kurzewski, M., Drozdzik, M., Borowiak-Palen, E., Synthesis, dispersion, and cytocompatibility of graphene oxide and reduced graphene oxide (2012) Colloids Surf., B, 89, pp. 79-85Chowdhury, S.M., Lalwani, G., Zhang, K., Yang, J.Y., Neville, K., Sitharama, B., Cell specific cytotoxicity and uptake of graphene nanoribbons (2013) Biomaterials, 34, pp. 283-293Faria, A.F., Martinez, D.S.T., Moraes, A.C.M., Maia Da Costa, M.E.H., Barros, E.B., Souza Filho, A.G., Paula, A.J., Alvez, O.L., Unveiling the role of oxidation debris on the surface chemistry of graphene through the anchoring of Ag nanoparticles (2012) Chem. Mater., 24, pp. 4080-4087Seabra, A.B., Paula, A.J., Duran, N., Redox-enzymes, cells and micro-organisms acting on carbon nanostructures transformation: A mini-review (2013) Biotechnol. Prog., 29, pp. 1-10Chng, E.L.K., Pumera, M., The Toxicity of graphene oxides: Dependence on the oxidative methods used (2013) Chemistry, 19, pp. 8227-823

How does the chain length of PEG functionalized at the outer surface of mesoporous silica nanoparticles alter the uptake of molecules?

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The current work describes the development of new mesoporous silica nanoparticles (MSNs) containing a high content of phenyl groups (hydrophobic species) inside the mesopores and externally functionalized with polyethylene glycol (PEG), a hydrophilic moiety, to provide biocompatibility and colloidal stability. The MSNs were encapsulated with curcumin, a versatile hydrophobic drug for biological use. The ability of silica nanoparticles to optimize the solubility of this biologically-active molecule in water was investigated. Nanoparticles were characterized using C-13 and Si-29 Nuclear Magnetic Resonance (NMR), thermal analysis (TGA and DTA), nitrogen sorption analysis, transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential (PZ). We assessed the curcumin water solubility using the pegylated nanoparticles as well as the influence of the PEG chain length (500 and 2000 Da) and its concentration on the encapsulation process. The results indicate that the higher the PEG chain length the lower the MSN encapsulation capacity for curcumin, possibly due to steric factors. However, all of the nanoparticles largely improved curcumin solubility in water.The current work describes the development of new mesoporous silica nanoparticles (MSNs) containing a high content of phenyl groups (hydrophobic species) inside the mesopores and externally functionalized with polyethylene glycol (PEG), a hydrophilic moie40980608067CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)sem informaçãoWe acknowledge financial support from CAPES, INCT-Inomat, Brazilian Nanotoxicology Network (Cigenanotox) and NanoBioss-SisNANO/MCT

Protein corona formation on magnetic nanoparticles conjugated with luminescent Europium complexes

CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOThe evaluation of the nanoparticles interactions with blood plasma enables a first and important insight on the organization of the adsorbed protein layer. In this context, we studied the formation of protein corona on magneto-luminescent Fe3O4@calix-Eu(TTA) nanoparticles in human plasma. The difference in the surface chemistry of F3O4 functionalized with calixarene (+30 mV zeta-potential) and europium (III) thenoyltrifluoroacetonate (Eu3+-TTA) complex (+7.4 mV zeta-potential) affected the colloidal stability and hard corona composition of the nanoparticles, which were monitored by SDS-PAGE gel electrophoresis, differential centrifugal sedimentation analyses and luminescence spectroscopy. Strikingly, after conjugation with Eu3+ TTA complex, the magnetic nanoparticles show lower adsorption affinity to proteins at higher blood plasma concentration. Moreover, the Eu3+ compound is featured with the narrow emission lines of D-5(0)-gt; F-7(J) (J=0-4) transitions, imparting additional characteristics to bifunctional nanoparticles that were used as probes to evaluate the protein corona formation.41212021208CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAUL

Surface Chemistry In The Process Of Coating Mesoporous Sio2 Onto Carbon Nanotubes Driven By The Formation Of Si-o-c Bonds.

The deposition of mesoporous silica (SiO(2)) on carbon nanotubes (CNTs) has opened up a wide range of assembling possibilities by exploiting the sidewall of CNTs and organosilane chemistry. The resulting systems may be suitable for applications in catalysis, energy conversion, environmental chemistry, and nanomedicine. However, to promote the condensation of silicon monomers on the nanotube without producing segregated particles, (OR)(4-x)SiO(x)(x-) units must undergo nucleophilic substitution by groups localized on the CNT sidewall during the transesterification reaction. In order to achieve this preferential attachment, we have deposited silica on oxidized carbon nanotubes (single-walled and multiwalled) in a sol-gel process that also involved the use of a soft template (cetyltrimethylammonium bromide, CTAB). In contrast to the simple approach normally used to describe the attachment of inorganic compounds on CNTs, SiO(2) nucleation on the tube is a result of nucleophilic attack mainly by hydroxyl radicals, localized in a very complex surface chemical environment, where various oxygenated groups are covalently bonded to the sidewall and carboxylated carbonaceous fragments (CCFs) are adsorbed on the tubes. Si-O-C covalent bond formation in the SiO(2)-CNT hybrids was observed even after removal of the CCFs with sodium hydroxide. By adding CTAB, and increasing the temperature, time, and initial amount of the catalyst (NH(4)OH) in the synthesis, the SiO(2) coating morphology could be changed from one of nanoparticles to mesoporous shells. Concomitantly, pore ordering was achieved by increasing the amount of CTAB. Furthermore, preferential attachment on the sidewall results mostly in CNTs with uncapped ends, having sites (carboxylic acids) that can be used for further localized reactions.173228-3

Advances In Dental Materials Through Nanotechnology: Facts, Perspectives And Toxicological Aspects.

Nanotechnology is currently driving the dental materials industry to substantial growth, thus reflecting on improvements in materials available for oral prevention and treatment. The present review discusses new developments in nanotechnology applied to dentistry, focusing on the use of nanomaterials for improving the quality of oral care, the perspectives of research in this arena, and discussions on safety concerns regarding the use of dental nanomaterials. Details are provided on the cutting-edge properties (morphological, antibacterial, mechanical, fluorescence, antitumoral, and remineralization and regeneration potential) of polymeric, metallic and inorganic nano-based materials, as well as their use as nanocluster fillers, in nanocomposites, mouthwashes, medicines, and biomimetic dental materials. Nanotoxicological aspects, clinical applications, and perspectives for these nanomaterials are also discussed.33621-63