Publications by authors named "Oswaldo L Alves"

Our research group previously studied the effectiveness of lipid-core nanocapsules (LNC) containing simvastatin (SV-LNC) in treating cognitive impairment in rats. While our results were promising, we needed to evaluate the potential toxicity of the nanoparticles themselves. This study aimed to compare the biochemical and hematological parameters of adult Wistar rats receiving LNC or SV-LNC to those receiving low doses of simvastatin crystals dispersed in a saline solution over 45 days.

View Article and Find Full Text PDF

This study aimed to incorporate β-AgVO and rGO into self-curing (SC) and heat-curing (HC) acrylic resins and to evaluate their physicochemical, mechanical, and antimicrobial properties while correlating them with the characterized material structure. Acrylic resin samples were prepared at 0 % (control), 0.5 %, 1 %, and 3 % for both nanoparticles.

View Article and Find Full Text PDF

Objective: The aim of this study was to evaluate the roughness, hardness, and color change of pit and fissure sealants of two commercial brands (Fluroshield ™ and Ultraseal XT ™) incorporated with nanostructured silver vanadate nanomaterial decorated with silver nanoparticles (β-AgVO) in concentrations (0% - control, 2.5% and 5%).

Material And Methods: Two commercial brands Fluroshield TM and Ultraseal XT ™ were used to make the samples with dimensions of 6 × 6 × 4 mm.

View Article and Find Full Text PDF

Mature landfill wastewater is a complex effluent due to its low biodegradability and high organic matter content. Currently, mature leachate is treated on-site or transported to wastewater treatment plants (WWTPs). Many WWTPs do not have the capacity to receive mature leachate due to its high organic load leading to an increase in the cost of transportation to treatment plants more adapted to this type of wastewater and the possibility of environmental impacts.

View Article and Find Full Text PDF

Palaemon pandalirformis (shrimp) is a species widely distributed in the Brazilian coastal region and with an important economic role. In addition, this organism is considered an indicator of environmental pollution in estuaries; however, its physiological responses to toxic environmental pollutants, including pesticides and nanomaterials, are not well known, mainly, the effects of co-exposure. Thus, the purpose of this study was to evaluate the ecotoxicological effects of co-exposure between oxidized multiwalled carbon nanotubes (HNO-MWCNT) and carbofuran pesticide on the routine metabolism of P.

View Article and Find Full Text PDF

Two-dimensional (2D) materials have emerged as an important class of nanomaterials for technological innovation due to their remarkable physicochemical properties, including sheet-like morphology and minimal thickness, high surface area, tuneable chemical composition, and surface functionalization. These materials are being proposed for new applications in energy, health, and the environment; these are all strategic society sectors toward sustainable development. Specifically, 2D materials for nano-imaging have shown exciting opportunities in and models, providing novel molecular imaging techniques such as computed tomography, magnetic resonance imaging, fluorescence and luminescence optical imaging and others.

View Article and Find Full Text PDF

This study aimed to evaluate two methods of the incorporation of nanostructured silver vanadate decorated with silver nanoparticles (AgVO) into acrylic resin and characterize the profile of early and late microbial communities in class and family taxonomic level by pyrosequencing. The specimens were made by adding different concentrations of AgVO (1, 2.5, and 5%) to the heat-activated acrylic resin by two methods: vacuum spatulation (VS) and polymeric film (PF).

View Article and Find Full Text PDF

The cytotoxic and genotoxic effects of commercial endodontic sealers (AH Plus, Sealer 26 and Endomethasone N) incorporated with nanostructured silver vanadate decorated with silver nanoparticles (AgVO - at concentrations 2.5, 5, and 10%) on human gingival fibroblast (HGF), and the silver (Ag ) and vanadium (V /V ) ions release were evaluated. Cytotoxicity, cell death, and genotoxicity tests were carried out with extract samples of 24-hr and 7-days.

View Article and Find Full Text PDF

This work reports an integrated nanosafety study including the synthesis and characterization of the graphene oxide-silver nanoparticle hybrid material (GO-AgNPs) and its nano-ecotoxicity evaluation in the zebrafish embryo model. The influences of natural organic matter (NOM) and a chorion embryo membrane were considered in this study, looking towards more environmentally realistic scenarios and standardized nanotoxicity testing. The nanohybrid was successfully synthesized using the NaBH aqueous method, and AgNPs (~ 5.

View Article and Find Full Text PDF

The development of cognitive impairment may be related to high levels of plasma cholesterol and obesity. Simvastatin (SV) and lovastatin (LV) are drugs that can potentially be used for the treatment of cognitive deficit. This study aimed to develop and characterize lipid-core nanocapsules (LNC) containing SV (SV-LNC) or LV (LV-LNC), evaluating the effects of SV-LNC in an animal model of cognitive deficit.

View Article and Find Full Text PDF

Camptothecin (CPT) is a potent antitumor drug frequently used in studies of drug delivery systems. The poor water solubility and unfavourable pharmacokinetic conditions of CPT and the development of nanomaterials such as mesoporous silica nanoparticles (MSNs), graphene oxide (GO) and a new family of GO decorated with MSNs (GO-MSNs) motivated the present work, which sought to solve these challenges. In this context, release assays showed rapid and prolonged release, respectively, by silica and GO/GO-MSN nanomaterials; release was faster at pH 7.

View Article and Find Full Text PDF

Statement Of Problem: Dental porcelain restorations are subject to biological failures related to secondary caries and periodontal disease leading to prosthesis replacement.

Purpose: The purpose of this in vitro study was to explore the microbiological and mechanical properties of dental porcelain incorporated with different percentages of silver vanadate (β-AgVO) through microbiological analysis, roughness tests, and the Vickers microhardness test.

Material And Methods: IPS InLine porcelain specimens were made by using a cylindrical Teflon matrix in the dimensions of 8×2 mm.

View Article and Find Full Text PDF

Graphene oxide (GO) is part of a new set of nanomaterials with particular characteristics related to its nanoscale size. Due to this feature, it presents high reactivity and other contaminants present in the environment could bind to them and affect its intrinsic toxicity. The metabolic effects of such nanomaterials and their combination with two common pollutants, zinc and cadmium, on the freshwater fish Geophagus iporangensis are analyzed.

View Article and Find Full Text PDF

The objective of this in vitro study was to investigate the effect of nanostructured silver vanadate decorated with silver nanoparticles (AgVO) on antimicrobial activity, hardness, roughness, and adhesion of a soft denture liner. The antimicrobial efficacy of the Trusoft (Boswoth) liner incorporated with different concentrations of AgVO against Enterococcus faecalis, Pseudomonas aeruginosa, Candida albicans, and Staphyloccocus aureus (n = 5) was evaluated by the agar diffusion method. Roughness, hardness, and adhesion properties were also evaluated.

View Article and Find Full Text PDF

Purpose: To evaluate the antimicrobial activity and physico-mechanical properties of an irreversible hydrocolloid in which nanostructured silver vanadate decorated with silver nanoparticles (AgVO ) was added at various concentrations (0% - control, 2.5%, 5%, and 10% by weight).

Materials And Methods: The agar diffusion method (n = 10) was used to evaluate the inhibitory effect on the following species: Streptococcus mutans, Staphyloccocus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans.

View Article and Find Full Text PDF

The incorporation of nanoparticles into endodontic sealers aims at increasing antimicrobial activity of the original material. The aim of this study is to incorporate the nanostructured silver vanadate decorated with silver nanoparticles (AgVO, at 2.5%, 5%, and 10%) into three endodontic sealers and evaluate the antibacterial activity of freshly sealers, surface topography and chemical composition, and setting time.

View Article and Find Full Text PDF

Graphene oxide (GO) has been evaluated for application in environmental remediation and pollution control strategies. However, the side effects caused by the interactions of GO with classical pollutants in aquatic environments are still largely unknown. In this work, the ecotoxicological effects of GO, cadmium, zinc and the interactions between GO and these trace elements (co-exposure) were evaluated through acute toxicity tests and routine metabolism (i.

View Article and Find Full Text PDF

Graphene oxide (GO) and silver nanoparticles (AgNPs) can be formed into a hybrid nanomaterial, known as GOAg nanocomposite, which presents high antibacterial activity. The successful translation of this nanomaterial into medical use depends on critical information about its toxicological profile. In keeping with a Safe-by-design approach, we evaluated the immunotoxicity of GOAg using J774 and primary murine macrophages.

View Article and Find Full Text PDF

In this work, we developed an integrative experimental design to investigate the long-term effects of two important classes of carbon nanomaterials with different dimensionalities (i.e., 1D oxidized multiwalled carbon nanotube, ox-MWCNT, and 2D graphene oxide, GO) on the development of the generalist insect Spodoptera frugiperda (Lepidoptera: Noctuidae).

View Article and Find Full Text PDF

The study of the toxic effect of carbofuran and multiwalled carbon nanotubes (MWCNTs) on Astyanax ribeirae metabolism is of paramount importance due to the increasing use of this pesticide in agriculture and in the production of nanotubes within the material industry. This study aimed to evaluate the effects of carbofuran, MWCNT, and the combination of these compounds on specific oxygen consumption and excretion of ammonia in A. ribeirae.

View Article and Find Full Text PDF

Objectives: This study characterized the microbial diversity of formed biofilm on the surface of acrylic resins modified with nanostructured silver vanadate decorated with silver nanoparticles (AgVO) after incubation in human saliva.

Design: Resin specimens prepared with AgVO at concentrations 0%, 1%, 2.5%, and 5% by either vacuum mixing or polymer solubilization were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

View Article and Find Full Text PDF
Article Synopsis
  • Graphene oxide (GO) was chemically modified with d-mannose (man-GO) to improve its properties for biomedical applications, confirmed by XPS and ATR-FTIR spectroscopy through specific binding energies and increased amine bond intensity.
  • Toxicity tests showed that man-GO is less harmful to human red blood cells compared to plain GO, indicating a significant reduction in hemolysis.
  • The study also identified 109 proteins in the man-GO's hard corona through LC-MS/MS, suggesting enhanced biocompatibility and potential for future use in medical applications.
View Article and Find Full Text PDF

Objectives: The objective of the study is to incorporate the nanostructured silver vanadate (AgVO) decorated with silver nanoparticles at endodontic sealers AH Plus, Sealapex, Sealer 26, and Endofill, at concentrations of 2.5%, 5%, and 10%, and to evaluate physical-chemical properties.

Materials And Methods: The study was to evaluate the radiopacity using digital radiography ( = 5), the tooth color change in 48 incisors ( = 3) for 7, 30, 90, and 180 days in a spectrophotometer, and the topographic distribution in a confocal laser ( = 5).

View Article and Find Full Text PDF

Palladium nanoparticles decorated reduced graphene oxide (Pd-rGO) and palladium nanoparticles intercalated inside nitrogen doped reduced graphene oxide (Pd-NrGO) hybrids have been synthesized by applying a very simple, fast and economic route using microwave-assisted in-situ reduction and exfoliation method. The Pd-NrGO hybrids materials show good activity as catalyst for ethanol electro oxidation for direct ethanol fuel cells (DEFCs) as compared to Pd-rGO hybrids. The enhanced direct ethanol fuel cell can serve as alternative to fossil fuels because it is renewable and environmentally-friendly with a high energy conversion efficiency and low pollutant emission.

View Article and Find Full Text PDF

Silver vanadates have been widely investigated because of their many interesting properties and their potential use in several applications. In addition to this, a large number of groups have investigated silver vanadates in the form of nanostructures. Here, we address first the synthesis and properties of nanosilver vanadate.

View Article and Find Full Text PDF