Cytotoxicity and Effects of a New Calcium Hydroxide Nanoparticle Material on Production of Reactive Oxygen Species by LPS-Stimulated Dental Pulp Cells

Introduction: The aim of this study was to synthesize and characterize calcium hydroxide (CH) nanoparticles [CH-NP] and compare the cytotoxicity of these materials with that of mineral trioxide aggregate (White MTA) in human dental pulp mesenchymal cells (hDPMCs) stimulated by lipopolysaccharide (LPS). Methods and Materials: The CH-NP were synthesized by the co-precipitation method, and the physical properties were investigated through X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive x-ray spectrometry (EDS). LPS-stimulated hDPMCs were placed in contact with different dilutions of culture media previously exposed to CH-NP and white MTA for 24 h. The groups were tested for cell viability by MTT formazan and Alamar Blue assays, the production of nitric oxide (NO) by Griess method and the production of reactive oxygen species (ROS) by means of the fluorescent oxidant-sensing probe 2’,7’-dichlorodihydrofluorescein diacetate (DCFH-DA). Control groups for viability test were maintained in DMEM (not LPS-stimulated). For NO and ROS production, negative control group was cells in DMEM, and positive control was cells stimulated by LPS. The results were statistically analyzed by two-way ANOVA, Tukey’s test and Dunnett’s test (ɑ=0.05). Results: The results showed that the cell viability remained above 50% in all materials, independent of the dilution in MTT formazan and Alamar Blue tests. MTA showed a reduction in NO production at dilutions of 1:4 to 1:32 compared with the positive control group (P<0.05). The tested materials exhibited lower ROS production by DPMCs than that by cells in the positive control group (P<0.05), and similar ROS production to the negative control group (P>0.05). Conclusion: The outcomes of present in vitro study showed that MTA and [CH-NP] were not cytotoxic materials, with MTA closer to the results of control group (DMEM). MTA and [CH-NP] reduced ROS production at basal levels, with MTA inhibiting NO production at higher dilutions

Biocompatible Magic Sized Quantum Dots: Luminescent Markers and Probes

Nanoscience and nanobiotechnology have aroused great academic and technological interest. Works relating biomaterials at the nanoscale can reach new biotechnologies and help in the development and use of tools for bioimage and diagnosis applications. In this work we demonstrated the advantages of magic sized quantum dots as luminescent markers and probes to bioimage applications. The visualization of MSQDs bioconjugated with biological probes in cells were performed at periods greater than 2 h, and visualization with no commercial dye would not be possible. Therefore, we demonstrated that theses biocompatible nanocrystals are luminescent markers and probes to diagnosis

Nanocomposite of Ag-Doped ZnO and AgO Nanocrystals as a Preventive Measure to Control Biofilm Formation in Eggshell and Salmonella spp. Entry Into Eggs

Salmonella spp. is an important foodborne agent of salmonellosis, whose sources in humans often include products of avian origin. The control of this bacterium is difficult especially when Salmonella spp. is organized into biofilms. We hypothesized that the novel nanocomposites of ZnO nanocrystals doped with silver (Ag) and silver oxide (AgO) nanocrystals (ZnO:Ag-AgO) synthesized by the coprecipitation method could control or prevent the formation of Salmonella Enteritidis (SE) and Salmonella Heidelberg (SH) biofilm and its entry into turkey eggs. The diffraction characteristics of ZnO and AgO showed sizes of 28 and 30 nm, respectively. The Zn to Ag substitution into the ZnO crystalline structure was evidenced by the ionic radius of Ag+2 (1.26 Å), which is greater than Zn+2 (0.74 Å). For the SE analyses post-biofilm formation, the ZnO:Ag-AgO was not able to eliminate the biofilm, but the bacterial load was lower than that of the control group. Additionally, SE was able to infiltrate into the eggs and was found in both albumen and yolk. For the SH analyses applied onto the eggshells before biofilm formation, the ZnO:Ag-AgO treatment prevented biofilm formation, and although the bacterium infiltration into the eggs was observed in all treated groups, it was significantly smaller in ZnO:Ag-AgO pre-treated eggs, and SH could not reach the yolk. There was no difference in pore size between groups; therefore, the inhibition of biofilm formation and the prevention of bacterium entry into the egg were attributable to the use of ZnO:Ag-AgO, which was not influenced by the egg structure. Although the amount of Ag and Zn in the shell of the ZnO:Ag-AgO group was greater in relation to the control, this difference was not detected in the other egg components. In the search for new measures that are effective, safe and viable for controlling microorganisms in poultry farming, the application of a nanocomposite of Ag-doped ZnO and AgO nanocrystals appears as an alternative of great potential to prevent Salmonella sp biofilms in eggshells and other surfaces

Biocompatibility of Doped Semiconductors Nanocrystals and Nanocomposites

Exposure of humans and environment to nanocrystals are inevitable, and nanotoxicological analyses are a requirement. The wide variety of nanocrystals with different applications is increasing, and characterization of their effects after exposure includes their potential toxicity and uses. This review summarizes the characterization of doped nanocrystals and nanocomposites, Ca-doped ZnO, Ag- and Eu-doped ZnO and Ni-doped ZnO NCs, their biocompatibility and applications. This review uncovers how these nanocrystals present desirable biocompatible properties, which can be useful as antitumoral and antimicrobial inducing agents, which differ markedly from toxic properties observed in other general nanocrystals

Fluorescent Markers: Proteins and Nanocrystals

This book chapter will comment on fluorescent reporter proteins and nanocrystals’ applicability as fluorescent markers. Fluorescent reporter proteins in the Drosophila model system offer a degree of specificity that allows monitoring cellular and biochemical phenomena in vivo, such as autophagy, mitophagy, and changes in the redox state of cells. Titanium dioxide (TiO2) nanocrystals (NCs) have several biological applications and emit in the ultraviolet, with doping of europium ions can be visualized in the red luminescence. Therefore, it is possible to monitor nanocrystals in biological systems using different emission channels. CdSe/CdS magic-sized quantum dots (MSQDs) show high luminescence stability in biological systems and can be bioconjugated with biological molecules. Therefore, this chapter will show exciting results of the group using fluorescent proteins and nanocrystals in biological systems

Pontos quânticos semicondutores sintetizados via soluções coloidais aquosas: estudos e aplicações nanobiotecnológicas

This work is based on the synthesis of CdSe e CdSe/CdSxSe1-x/CdS magic sized quantum dots, as well as CdSe e CdSe/CdSxSe1-x/CdS ultrasmall quantum dots in aqueous solutions. The physics properties of quantum dots were investigated using various experimental techniques and theoretical models. The modifications in the phonon confinement Gaussian model were done to perform a more realistic description of the shell and the alloy effects in quantum dots CdSe/CdSxSe1-x/CdS in the Raman Spectra. Two methods were developed, one synthesized a quantum dot magic size (MSPQs) and it was able to control the shell thickness CdS around the MSPQs depending on the synthesis temperature, and the second was obtained through the quantum dots ultrasmall, which the thickness of the shell CdS was monitored as a function of the stabilizer concentration. In addition, the results the MSPQs were functionalized with chemicals groups that may be bioconjugated. It was demonstrated that the MSPQs were not immunogenic and did not exhibit cytotoxic effects. Thus, the MSPQs were covalently bond to aspecificantibody for breast cancer targeting its use with a luminescent probe.Fundação de Amparo a Pesquisa do Estado de Minas GeraisDoutor em FísicaNesta pesquisa sintetizou-se pontos quânticos de CdSe e CdSe/CdSxSe1-x/CdS de tamanhos mágicos, além de CdSe e CdSe/CdSxSe1-x/CdS de tamanhos ultra pequenos em soluções aquosas. As propriedades físicas dos pontos quânticos foram investigadas através de várias técnicas experimentais e modelos teóricos. Foram realizadas modificações no modelo de confinamento de fônons Gaussiano a fim de realizar uma descrição mais real da casca e efeitos da liga em pontos quânticos de CdSe/CdSxSe1-x,/CdS nos espectros Raman. Duas metodologias foram desenvolvidas, uma que sintetiza pontos quânticos de tamanhos mágicos MSPQs, a qual permite controlar a espessura da casca de CdS ao redor dos MSPQs em função da temperatura de síntese, e a outra obtida através dos pontos quânticos de tamanhos ultra pequenos, em que a espessura da casca de CdS foi controlada em função da concentração de estabilizante. Além destes resultados, foram funcionalizados os MSPQs com grupamentos químicos para a bioconjugação. Demonstrou-se que os MSPQs apresentam baixa citotoxicidade e nenhuma resposta imunogênica. Dessa forma, foram acoplados covalentemente os MSPQs a um anticorpo específico de câncer de mama visando a sua utilização com uma sonda luminescente

Simonkolleite nanoparticles for seed treatment and control of tomato bacterial spot caused by Xanthomonas hortorum pv. gardneri

ABSTRACT Bacterial spot caused by Xanthomonas spp. (X. vesicatoria, X. euvesicatoria pv. euvesicatoria, X. euvesicatoria pv. perforans, and X. hortorum pv. gardneri) may result in significant losses for tomato crops. Simonkolleite nanoparticles (SK-NPs) has been indicated as a novel approach for plant disease control. The objective of this work was to evaluate SK-NPs (ZnOCl, ZnOCl:Ag, and ZnOCl:Cu at different concentrations) for the in vitro inhibition of X. hortorum pv. gardneri, determining the time of exposure of the products for the bacterial death; the reduction of bacteria recovery on inoculated seeds, and their efficacy to reduce bacterial spot severity in plant. The growth inhibition was evaluated by inhibition zone in culture medium plates, when the diameter of the inhibition zone was measured. The period of exposure of the products to the bacterial suspension tested were 1, 2, 3, 4, or 5 h. Tomato inoculated seeds were treated with SK-NPs. In plant, the preventive and curative effects were evaluated by applying the products two days before or after inoculation, respectively. Disease severity was evaluated and the area under the disease progress curve (AUDPC) was calculated. ZnOCl:Ag, ZnOCl:Cu, and ZnOCl inhibited bacterial growth, and the 5 h exposure time was necessary to reduce bacterial growth. ZnOCl:Ag, and ZnOCl:Cu reduced the bacteria presence in the seeds, and did not affect the seed germination. Both products reduced the AUDPC in the preventive application. The use of SK-NPs ZnOCl:Ag and ZnOCl:Cu showed to be promising to manage tomato bacterial spot

First evidence of crystalline KHSO(4):Mn grown by an aqueous solution method and the investigation of the effect of ionizing radiation exposure

In this work, KHSO(4):Mn crystals doped with Mn and K(2)SO(4) were synthesized using an aqueous solution method. The samples were exposed to ionizing radiation in order to observe the effects on their physical properties. Raman spectroscopy was used to identify the structure of the crystals by detecting the vibrational frequencies of the crystalline lattice. Electron paramagnetic resonance (EPR) was used to study the creation of paramagnetic centers arising from exposure to ionizing radiation. This new synthesis method produces high quality K(2)SO(4) and KHSO(4):Mn crystals and allows control of structural, morphological, optical and magnetic properties. (C) 2009 Elsevier B.V. All rights reserved,Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)FAPEMIGMCT/CNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Thermal and structural analysis of Li2O ⋅ B2O3 ⋅ Al2O3 glasses with addition of CaF2 or LiF

The thermal and structural properties of a Li2O ⋅ B2O3 ⋅ Al2O3 glass matrix with the addition CaF2 or LiF were investigated by XRD and DTA. The results showed that the samples are glasses. The thermal analysis also showed a trend of the glass transition temperature shifting to lower temperatures, and the shift or new peaks of crystallization is observed as the LiF and CaF2 content goes up. The glass-forming tendency (GFT), thermal stability (TS) and the Reduced glass transition temperature (TgR) are discussed as a function of composition and results indicate that this parameters are highly sensitive to different composition