Maria Luiza Fascineli

Experimental investigation of the coprecipitation method: an approach to obtain magnetite and maghemite nanoparticles with improved properties

Iron oxides that exhibit magnetic properties have been widely studied not only from an academic standpoint, but also for numerous applications in different fields of knowledge, such as biomedical and technological research. In this work, magnetite and maghemite nanoparticles were synthesized by chemical coprecipitation of FeCl2ċ4H2O and FeCl3ċ6H2O (proportion of 1 : 2) in three different cases using two bases (sodium hydroxide and hydroxide ammonium) as precipitants. The chemical coprecipitation method was selected for its simplicity, convenience, reproducibility, and low cost in the use of glassware. The nanostructured materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and magnetometry (VSM). The objective of this work is to study the variation in the morphological characteristics and physical properties of nanoparticles magnetic as a function of the different production processes. As observed by TEM, the materials obtained from the precipitating agent NH4OH are more uniform than those obtained with NaOH. From XRD pattern analysis, it appears that the obtained materials correspond to magnetite and maghemite and, from magnetometry VSM analysis, show high magnetization as a function of the magnetic field at room temperature, indicating that these materials are superparamagnetic.

Avaliação da toxicidade aguda e potencial neurotóxico do óleo-resina de copaíba (Copaifera reticulata Ducke, Fabaceae)

Copaiba oil-resin obtained from Copaifera L. genus, Fabaceae, is largely used in popular medicine as antinflammatory, antimicrobial and antitumoral. Information concerning the potential toxicity of this oil is limited in the literature. The goal of this study was to investigate the acute toxicity and the possible neurotoxic effects related to the ingestion of Copaifera reticulata Ducke, Fabaceae, oil-resin using female Wistar rats. Fifteen nulliparous rats were used and distributed in the experimental groups orally exposed to doses of 300 e 2000 mg/kg bw of oil-resin (gavage). No overt clinical signs of toxicity or neurotoxicity, alteration of food consumption or body weight were observed in the animals at the tested doses. The lethal oral toxicity was estimated to be higher than 2000 mg/kg bw, classified as category 5 according to OECD Guide 423. These results indicate that there is a certain safety margin associated with the use of copaiba as therapeutic agent, although additional toxicological studies are still necessary, mainly using repeated low doses.

Photodynamic therapy mediated by acai oil (Euterpe oleracea Martius) in nanoemulsion: A potential treatment for melanoma.

Melanoma is the most aggressive and lethal form of skin cancer, responsible for >80% of deaths. Standard treatments for late-stage melanoma usually present poor results, leading to life-threatening side effects and low overall survival. Thus, it is necessary to rethink treatment strategies and design new tools for the treatment of this disease. On that ground, we hereby report the use of acai oil in nanoemulsion (NanoA) as a novel photosensitizer for photodynamic therapy (PDT) used to treat melanoma in in vitro and in vivo experimental models. NIH/3T3 normal cells and B16F10 melanoma cell lines were treated with PDT and presented 85% cell death for melanoma cells, while maintaining high viability in normal cells. Flow cytometry indicated that cell death occurred by late apoptosis/necrosis. Tumor bearing C57BL/6 mice treated five times with PDT using acai oil in nanoemulsion showed tumor volume reduction of 82% in comparison to control/tumor group. Necrotic tissue per tumor area reached its highest value in PDT-treated mice, supporting PDT efficacy. Overall, acai oil in nanoemulsion was an effective photosensitizer, representing a promising source of new photosensitizing molecules for PDT treatment of melanoma, a tumor with an inherent tendency to be refractory for this type of therapy.

The lipidome, genotoxicity, hematotoxicity and antioxidant properties of andiroba oil from the Brazilian Amazon

Abstract Andirobeira is an Amazonian tree, the seeds of which produce a commercially valuable oil that is used in folk medicine and in the cosmetic industry. Andiroba oil contains components with anti-inflammatory, cicatrizing and insect-repellant actions. However, virtually nothing is known of the safety of this oil for humans. The aim of this work was therefore to investigate the hematotoxicity, genotoxicity and mutagenicity of andiroba oil using the comet and micronucleus assays, and to assess its antioxidant properties and lipidome as a means of addressing safety issues. For the experiments, andiroba oil was administered by gavage for 14 consecutive days in nulliparous female Swiss mice randomly distributed in four groups: negative control and three doses of oil (500, 1000 and 2000 mg/kg/day). These doses were chosen based on recommendations of the OECD guideline no. 474 (1997). GC/MS was used to investigate the free fatty acid, cholesterol and triterpene content of andiroba oil in a lipidomic analysis. No clinical or behavioral alterations were observed throughout the period of treatment, and exposure to andiroba oil at the doses and conditions used here did not result in hematotoxic, genotoxic or mutagenic effects. Tests in vitro showed that oil sample 3 from southwestern of Brazilian Amazon had a high antioxidant capacity that may protect biological systems from oxidative stress, although this activity remains to be demonstrated in vivo.

Andiroba Oil (Carapa guianensis Aublet) Nanoemulsions: Development and Assessment of Cytotoxicity, Genotoxicity, and Hematotoxicity

Andiroba oil (AO) is obtained from an Amazonian plant and is used in traditional medicine. We carried out a comparative study to test the cytotoxicity, genotoxicity, and hematotoxicity of the oil and its nanoemulsion (AN) in vitro (fibroblasts, lineage NIH/3T3) and in vivo (Swiss mice). The AN was characterized by DLS/Zeta, and its stability was investigated for 120 days. The biological activity of AN was assessed in vitro by MTT test and cell morphology analyses and in vivo by micronucleus, comet, and hematotoxicity tests. The AN presented a hydrodynamic diameter (Hd) of and PDI of and good stability at room temperature. The MTT test evidenced the cytotoxicity of AO and of AN only at their highest concentrations, but AN showed lower cytotoxicity than AO. A lower cytotoxicity of AN, when compared to AO, is in fact an interesting data suggesting that during therapeutic application there will be a lower impact in the cell viability of healthy cells. Cytotoxicity, genotoxicity, and hematotoxicity were not observed in vivo. These tests on the biological and toxicological effects of andiroba oil and nanostructured oil are still initial ones but will give a direction to future application in cosmetics and/or the development of new phytotherapics.

HPLC-FLD method for itraconazole quantification in poly lactic-co-glycolic acid nanoparticles, plasma and tissue

Itraconazole, a broad-spectrum anti-fungal, has many side effects, and nanosystems for drug delivery have been proposed as a method to optimize the drugs pharmacokinetics and reduce side effects. An high performance liquid chromatography (HPLC) procedure using fluorometric detection was developed for determination of itraconazole in polymeric poly(lactic-co-glycolic acid) nanoparticles, plasma and tissue. Linearity, limits of detection and quantification, recovery, precision, selectivity and stability were established. The developed method was tested in itraconazole detection and quantification of biodistribution of nanoparticles administered intraperitoneally to Balb/C female mice. This study developed an analytical method for HPLC with fluorometric detection for quantification of itraconazole in polymeric nanoparticles, tissue and plasma, which is sensitive, low cost, viable for routine usage and with potential for application in itraconazole biodistribution and pharmacokinetics studies.

Humic acid attenuation of silver nanoparticle toxicity by ion complexation and the formation of a Ag3+ coating

The use of silver nanoparticles (AgNPs) result in an inevitable contact with aquatic environments. Here we study the behavior of AgNPs and the developmental toxicity in zebrafish embryos exposed to these nanoparticles (0-10 mg/L) with and without the presence of HA (20 mg/L), using zebrafish facility water (ZFW) and zebrafish growing media (ZGM). The presence of cations and HA gave rise to a decrease in Ag ion release and ζ-potential, an increase in the hydrodynamic diameter and oxidation of the AgNP surface. The results show that the presence of HA and cations in the media, as well as the silver speciation, i.e., the unusual presence of Ag3+, decreases the toxicity of AgNPs (LC50AgNPs: 1.19 mg/L; LC50AgNPs + HA: 3.56 mg/L), as well as silver bioavailability and toxicity in zebrafish embryos. Developmental alterations and the LC50 (1.19 mg/L) of AgNPs in ZFW were more relevant (p ≤ 0.05) than for AgNPs in ZGM (LC50 ˃ 10 mg/L). It was demonstrated that the bioaccumulation and toxicity of AgNPs depends on several factors including AgNPs concentration, nanoparticle aggregation, dissolved silver ions, speciation of silver ions, the amount of salt in the environment, the presence of humic substances and others, and different combinations of all of these factors.

Genotoxic and histopathological biomarkers for assessing the effects of magnetic exfoliated vermiculite and exfoliated vermiculite in Danio rerio.

Magnetic exfoliated vermiculite is a synthetic nanocomposite that quickly and efficiently absorbs organic compounds such as oil from water bodies. It was developed primarily to mitigate pollution, but the possible adverse impacts of its application have not yet been evaluated. In this context, the acute toxicity of magnetic exfoliated vermiculite and exfoliated vermiculite was herein assessed by genotoxic and histopathological biomarkers in zebrafish (Danio rerio). DNA fragmentation was statistically significant for all groups exposed to the magnetic exfoliated vermiculite and for fish exposed to the highest concentration (200mg/L) of exfoliated vermiculite, whereas the micronucleus frequency, nuclear abnormalities and histopathological alterations were not statistically significant for the fish exposed to these materials. In the intestinal lumen, epithelial cells and goblet cells, we found the presence of magnetic exfoliated vermiculite and exfoliated vermiculite, but no alterations or presence of the materials-test in the gills or liver were observed. Our findings suggest that the use of magnetic exfoliated vermiculite and exfoliated vermiculite during standard ecotoxicological assays caused DNA damage in D. rerio, whose alterations may be likely to be repaired, indicating that the magnetic nanoparticles have the ability to promote genotoxic damage, such as DNA fragmentation, but not mutagenic effects.

Hematotoxicity of magnetite nanoparticles coated with polyethylene glycol: in vitro and in vivo studies

Hematotoxicity of magnetite nanoparticles coated with dimercaptosuccinic acid (DMSA) and polyethylene glycol (PEG) has been evaluated by determining their safety in vitro and in vivo in a rat model up to 30 days after administration of a single dose. The in vitro analysis consists of global plasma coagulation (PT, aPTT, and fibrinogen) and platelet aggregation tests while the hematotoxicity studies in vivo include a complete blood count and the possible genotoxic effect analysis in the bone marrow hematopoietic function. Prolonged aPTT values indicate a higher anticoagulant effect for NP-DMSA compared with PEG-coated nanoparticles as a consequence of the higher surface charge of the former. The in vivo tests showed that these bioferrofluids do not cause genotoxic effects, affect erythropoiesis or increase the number of immature erythrocytes in the bone marrow at the analyzed dose. However, nanoparticle administration showed a significant effect on the leukocyte counts in animals treated with DMSA coated nanoparticles 24 h after injection. This response is not observed in animals treated with PEG modified nanoparticles which justifies the use of this polymer in biomasking strategies.

Effects of ashes from a Brazilian savanna wildfire on water, soil and biota: An ecotoxicological approach

Wildfire is very common in Brazilian savannas, and its effects on water, soil and aquatic/soil organisms are poorly understood. In this study, we observed the effects of fire, especially of ashes, on surface soil and subsurface water in a typical Brazilian savanna (Cerrado sensu strictu) for one year. Soil analyses (pH, organic matter content, potential acidity, K, Ca, Mg and P) and subsurface water analyses (NO3-, PO43- Mg2+, Ca2+ and K+) were assessed. We evaluated the ecotoxicological effects of ashes on three different endpoints and species, in fish Danio rerio (embryonic development), aquatic snail Biomphalaria glabrata (reproduction) and a soil species Enchytraeus sp. (reproduction). We found a higher amount of exchangeable cations and organic matter content in short-term fire effects on soil, but the higher availability of nutrients did not affect the soil pH in field plots. The effects of ashes on soil and subsurface water did not persist for one-year post-fire, except for organic matter content in burned areas. No toxic effects were observed on hatching success and incidences of developmental abnormalities in D. rerio embryos. However, ash input had adverse effects on reproduction in snails and enchytraeids. We reported a statistically significant decrease in snail eggs exposed to the 50g.L-1 and 100g.L-1 of ashes after four weeks (p<0.05, Dunnetts test and Tukey test). Enchytraeus sp. reproduction was negatively influenced by the natural soil, which presents high acidity, and also when exposed directly to the ashes from burned area, suggesting that pH and other ash compounds may limit the growth of enchytraeids. More studies in burned areas are strongly encouraged, addressing the potential important routes of exposure to ashes in order to understand the impact of intense fires on soil and aquatic biota in tropical savannas.