Erasmo Orrantia-Borunda

Cytotoxicity of functionalized carbon nanotubes in J774A macrophages

Cytotoxicity of carbon nanotubes (CNTs) is a prime concern for its use as antigen carriers. Here we evaluated the cytotoxic effect of unpurified (UP-CNTs), purified (P-CNTs), fluorescein isothiocyanate-functionalized (FITC-CNTs), and Entamoeba histolytica 220-kDa lectin-functionalized CNTs (L220-CNTs) in J774A macrophage (MOs) cell line. Cell viability and apoptosis were analyzed by MTT and TUNEL assays, respectively. Cyclooxygenase-2 (COX-2) was analyzed by reverse transcription-polymerase chain reaction. Cytotoxicity at 6.0 mg/L was higher with UP-CNTs > P-CNTs > FITC-CNTs, showing a decrease in cell viability and an increase in apoptosis. In contrast, MOs interacted with L220-CNTs showed an increase in cell viability without signs of apoptosis. Although UP-CNTs and P-CNTs exhibited COX-2 induction with 6.0 mg/L, functionalized CNTs were able to induce COX-2 at concentrations as low as 0.06 mg/L. These results suggest that functionalization decreases toxicity, and that L220-CNTs may be an excellent candidate for the production of a nanovaccine against amebiasis.

Effect of cuo nanoparticles over isolated bacterial strains from agricultural soil

The increased use of the nanoparticles (NPs) on several processes is notorious. In contrast the ecotoxicological effects of NPs have been scarcely studied. The main current researches are related to the oxide metallic NPs. In the present work, fifty-six bacterial strains were isolated from soil, comprising 17 different OTUs distributed into 3 classes: Bacilli (36 strains), Flavobacteria (2 strains), and Gammaproteobacteria (18 strains). Copper oxide nanoparticles (CuONPs) were synthesized using a process of chemical precipitation. The obtained CuONPs have a spherical shape and primary size less than 17 nm. Twenty-one strains were used to evaluate the cytotoxicity of CuONPs and 11 of these strains showed high sensibility. Among those 11 strains, 4 (Brevibacillus laterosporus strain CSS8, Chryseobacterium indoltheticum strain CSA28, and Pantoea ananatis strains CSA34 and CSA35) were selected to determine the kind of damage produced. The CuONPs toxic effect was observed at expositions over 25mgċL-1 and the damage to cell membrane above 160mgċL-1. The electron microscopy showed the formation of cavities, holes, membrane degradation, blebs, cellular collapse, and lysis. These toxic effects may probably be due to the ions interaction, the oxide-reduction reactions, and the generation of reactive species.

Cytotoxicity of carbon nanotubes on J774 macrophages is a purification-dependent effect

The cytotoxicity of the carbon nanotubes (CNTs) is an important factor for the manufacture of nanovaccines. The aim of this work was to evaluate the relationship of the purification method of CNTs in cellular toxicity using macrophages (MOs) from the J774 cell line. Viability test was performed with MTT assays at 24 h of exposure at concentrations of 0.06, 0.6, and 6 mg/L of unpurified (UP-CNTs) or purified (P-CNTs) CNTs by two different methods: (1) reflux with 3M HNO3 and (2) sonication in H2SO4/HNO3. Characterization and COOH content of CNTs was performed using scanning electron microscopy, raman spectroscopy, and titration with NaHCO3. P-CNTs1 had lengths >100 µm and 2.76% COOH content, while P-CNTs2 had lengths >1 µm and 7% COOH content. This last particle showed a lower toxic effect. The results suggest that the lenght and COOH content are important factors in the toxicity of the CNTs.

Cell wall damage and oxidative stress in Candida albicans ATCC10231 and Aspergillus niger caused by palladium nanoparticles

In this work the toxic effect of Palladium nanoparticles (PdNPs) was investigated in two eukaryotic cell models, Candida albicans and Aspergillus niger. PdNPs were synthesized by chemical reduction method, obtaining spherical NPs with a primary size ranging from 3 to 15 nm. PdNPs showed a hydrodynamic size of 1548 nm in Lees minimum media. Minimal inhibitory concentration was determined at 200 and 250 ppm for Candida albicans and Aspergillus niger respectively, revealing a significant cell growth inhibition (ANOVA and tukey analysis, α = 0.5). Reactive Oxygen Species levels were increased in both microorganisms. Confocal, scanning and transmission electron microscopy studies revealed cell wall damage and cellular morphology changes, induced by the interaction of PdNPs, in both microorganisms.

Kinetics for an Optimized Biosynthesis of Silver Nanoparticles Using Alfalfa Extracts

Abstract In recent years, great efforts have been directed to provide eco-friendly methods for nanoparticles (NPs) synthesis. In this endeavor, it is desired that polydispersity be as narrow as possible and that the chemical and physical properties can be controlled. In this work, silver nanoparticles (SNPs) were obtained by means of (a) a green approach (biosynthesis) using alfalfa extracts; and (b) a thermal decomposition method in organic media. As per biosynthesis, pH, initial concentration of precursor (Ag+) and extraction solvent of plant metabolites were varied in order to identify the conditions where SNP polydispersity presented a best value. When these conditions were determined, the reaction kinetics was evaluated. The rate constant and order of reaction were 7.33×10−6 L3.6/mol3.6 s, and 4.6, respectively. Also, in the biosynthesis, it was found that the size and the degree of polydispersity depend on initial concentration of precursor and the type of extractant. Thermal decomposition was performed using silver oleate as precursor in order to compare characteristics of the NPs obtained by both biosynthesis and the chemical method. According to our results, SNPs obtained through thermal decomposition showed a lower polydispersity and higher degree of crystallinity than those obtained using biosynthesis. However, the green method eliminates the use of toxic compounds, which is extremely important if these particles are intended for biomedical purposes. In addition, this is a less expensive method as compared to other chemical methods. To our knowledge, this is one of the few reports analyzing the reaction kinetics, which is extremely important if scale-up is intended.

Cytotoxicity of Protein-Carbon Nanotubes on J774 Macrophages Is a Functionalization Grade-Dependent Effect

Carbon nanotubes (CNTs) are used as carriers in medicine due to their ability to be functionalized with chemical substances. However, cytotoxicity analysis is required prior to use for in vivo models. The aim of this study was to evaluate the cytotoxic effect of CNTs functionalized with a 46 kDa surface protein from Entamoeba histolytica (P46-CNTs) on J774A macrophages. With this purpose, CNTs were synthesized by spray pyrolysis and purified (P-CNTs) using sonication for 48 h. A 46 kDa protein, with a 4.6–5.4 pI range, was isolated from E. histolytica HM1:IMSS strain trophozoites using an OFFGEL system. The P-CNTs were functionalized with the purified 46 kDa protein, classified according to their degree of functionalization, and characterized by Raman and Infrared spectroscopy. In vitro cytotoxicity was evaluated by MTT, apoptosis, and morphological assays. The results demonstrated that P46-CNTs exhibited cytotoxicity dependent upon the functionalized grade. Contrary to what was expected, P46-CNTs with a high grade of functionalization were more toxic to J774 macrophages than P46-CNTs with a low grade of functionalization, than P-CNTs, and had a similar level of toxicity as UP-CNT. This suggests that the nature of the functionalized protein plays a key role in the cytotoxicity of these nanoparticles.