
Luiz GasparottoFederal University of Mato Grosso do Sul · INQUI
Luiz Gasparotto
PhD
About
66
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Introduction
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Education
September 2007 - December 2008
May 2006 - March 2009
June 2005 - July 2007
Publications
Publications (66)
Settled barite is a known challenge in well construction and well control activities. This phenomenon creates operational and safety challenges during cut and put operations in well abandonment activities. In this paper, we introduce a novel approach to mitigate these challenges by dispersing settled barite particles using chelating agents, specifi...
In the present study, pyroligneous acid, also known as wood vinegar, has been employed as reducing and stabilizing agent in the synthesis of silver nanoparticles (AgNPs) anchored on nanocellulose (NC). The idea is to confer the latter bactericidal properties for its typical uses such as in cosmetics and food-packing. It has been demonstrated that A...
Geopolymers are the most promising alternative to Ordinary Portland Cement for oil-well cementing and well abandonment. To that end, the slurry needs a required pumping time ensured by the addition of retarders. Although zinc has been widely known to prolong the setting time of geopolymers, its mechanism of action has yet to be fully elucidated. It...
In the present study, we demonstrate that pyroligneous acid (PA), also known as wood vinegar, functions efficiently as both reducing and stabilizing agent in the synthesis of silver nanoparticles (AgNPs). The synthesis and stabilization of AgNPs take place in the following fashion: 1) in alkaline environment, oxygenated species (phenols in the pres...
Aims:
A paper by Araújo et al. (2018) claims that a variety of compounds present in pyroligneous acid (guaiacol, phenols and furfural) are responsible for the observed antimicrobial activity. We show, on the other hand, that the low pH due to acetic acid present in pyroligneous acid is the real cause of the activity METHODS AND RESULTS: pyroligneo...
Herein we report the successful synthesis of stable silver nanoparticles (AgNPs) using 1,1′-(quinoxaline-2,3-diylbis(azanediyl))diethanol (QX) as the only stabilizer. The QX-AgNPs system was then employed as chromogenic probe for the selective detection of L-cysteine (Cys), Mg²⁺, and Sn²⁺ in the presence of interfering species. We discuss the role...
Despite the fact that silver nanoparticles (AgNPs) have been widely studied in medical and correlated fields, details on their mechanisms are yet to be fully understood. Herein we present the first study on the combination of infrared spectroscopy and chemometrics as an analytical tool to investigate the mechanism of action of AgNPs against Escheri...
Background:
Oral mucositis (OM) is a severe inflammation of the oral mucosal cells associated with chemotherapy and/or radiotherapy-induced toxicity, resulting in epithelial ulcers and higher risk of death from sepsis. The aim of the present study was to evaluate the nanoparticle (AuNp) effect on OM induced in hamsters.
Materials and methods:
5-...
For many cancers, early detection is the key to improve survival and reduce the morbidity, which is associated with radical resections due to late diagnosis. Here, we describe the efficiency of primary antibody-conjugated gold nanoparticles (AuNPs) to specifically target chronic inflammatory processes, specially M2 macrophages, in tissue sections o...
Natural products-mediated synthesis has become quite an interesting route for the ecofriendly production of nanomaterials. However, products employed in natura may require long reaction times and high temperatures that lead to non-ideal particle-size distribution. In this work, we developed an optimized one-pot synthesis of silver nanoparticles usi...
Chemical Oxygen Demand (COD) is a quality parameter of superficial water and wastewater that provides information on chemically degradable fractions of organic (and inorganic) pollutants. Although firmly established, the conventional colorimetric method certified by Standard Methods for the Examination of Water and Wastewater of the American Societ...
The development of nanoprobes for selective detection of metal ions in solution has attracted great attention due to their impact on living organisms. As a contribution to this field, this paper reports the synthesis of silver nanoparticles modified with rutin in the presence of ascorbic acid and their successful use as a chromogenic probe for the...
Abstract: The study and preparation of new nanostructures involving the integration of distinct nanomaterials have been important for the development of new electrochemical devices for (bio)sensing and energy storage. Such devices envisage miniaturized or flexible electronic equipment for emerging technologies, including adaptive displays, artific...
Quinoxaline derivatives have attracted considerable attention due to their vast range of applications that includes electroluminescence and biomedicine. Concerning the latter, the literature has shown that compounds with a quinoxaline motif bind quite efficiently to phosphatidylinositol-4,5-bisphosphate 3-kinases (PI3Ks), which are enzymes found to...
One of the most elusive concepts in electrochemistry is that of electromotive force (EMF). Often students, and even instructors, mistakenly take it as “electric potential difference” (EPD) or “voltage difference”. To clarify this issue properly, here we demonstrate an activity that was conducted with readily available and inexpensive resources. We...
In a previous paper (RSC Adv., 2015, 5, 66886–66893), we showed that the combination of silver nanoparticles (NanoAg) with doxycycline (DO) culminated in an increased bactericidal activity towards E. coli. Herein we further investigated the metabolic changes that occurred on Staphylococcus aureus upon exposure to NanoAg with the help of attenuated...
This study aimed to elucidate the anti-inflammatory, anti-oxidant and antifibrotic effects of gold nanoparticles (GNPs) in rats subjected to liver injury with ethanol and Methamphetamine (METH).The liver injury was induced by gavage administrations of 30% alcoholic solution (7 g/kg) once a day during 28 days, followed by METH (10 mg/kg) on the 20th...
Understanding the interactions between nanoparticles and biological surfaces is of great importance for many areas of nanomedicine and calls for detailed studies at the molecular level using simplified models of cellular membranes. In this paper, waterdispersed polyvinylpyrrolidonestabilized gold nanoparticles (AuNPs) were incorporated in floating...
In cancers, apoptosis signaling pathways and cell survival and growth pathways responsible for resistance to conventional treatments, such as Pi3K/Akt/mTOR and mitogen-activated protein kinase (MAPK) become dysregulated. Recently, alternative treatments to promote tumor cell death have become important. The present study reports on the antitumor an...
In this work we obtained gold nanoparticles (NanoAu) through a low environmental impact pathway. Gold nanoparticles (GNPs) are considered the potential platforms for drug delivery, to know their activity we tested their antitumor against HT-29 cells. For this study we used viability test, evaluation in vitro cell death and immunofluorescence micros...
In cancers, apoptosis signaling pathways and cell survival and growth pathways responsible for resistance to conventional treatments, such as Pi3K/Akt/mTOR and mitogen-activated protein kinase (MAPK) become dysregulated. Recently, alternative treatments to promote tumor cell death have become important. The present study reports on the antitumor an...
The antimicrobial property of silver nanoparticles (AgNPs) is believed to be associated to their interaction with biointerfaces such as microbial cell membranes, encouraging research on the identification of membrane sites capable of AgNPs binding. Although significant progress has been made in that regard, the exact molecular mechanism of action i...
We show that sodium 9,10-epoxy-12-hydroxytetradecanoate (SEAR), an epoxidized derivative of ricinoleic acid, simultaneously functioned as reducing and stabilizing agents in the synthesis of silver nanoparticles in alkaline aqueous medium. The advantage of using SEAR is its biodegradability and nontoxicity, which are important characteristics for mi...
Herein, we report damped and stationary oscillations during Formic Acid oxidation (FAO) under galvanostatic control in a Direct Formic Acid fuel cell (DFAFC). Using Pt/C catalyst in a practical DFAFC, the anodic electrode are allowed to rise its potential up to 600 mV, at the most, which, in turn leads to solely presence of damped oscillations duri...
we show, for the first time, that gold nanoparticles (AuNPs) synthesized by a simple, inexpensive, and environmentally-correct method can be easily conjugated with the antibodies anti-COX-2 to specifically parafinized tissue of inflammatory process. The antibody/AuNPs conjugates were then successfully applied for imaging with fluorescence confocal...
Background
gold nanoparticles (GNPs) are regarded as potential platforms for drug delivery. However, their interaction with live organisms must be understood prior to their utilization as drug carriers. The present study reports the anti-inflammatory, analgesic and anti-tumor effects of GNPs. The biodistribution of GNPs and their effect on various...
In the present study, poly(vinylpyrrolidone) (PVP) served as reducing and capping agents for the synthesis of gold nanoparticles (AuNPs) in alkaline medium. The PVP-AuNPs were then combined with carbon nanotubes (CNTs) to assemble thin films onto ITO via the layer-by-layer (LbL) technique. The PVP-AuNPs/CNTs LbL films were analyzed with UV–Vis spec...
This article proposes an indirect method to evaluate the corrosion rate of iron nail in simulated seawater. The official procedure is based on the direct measurement of the specimen's weight loss over time; however, a highly precise scale is required and such equipment may not be easily available. On the other hand, mobile phones equipped with good...
The present work describes a microcontrolled photometer based on light-emitting-diodes (LED) for detection of Pb2+ using gold nanoparticles (AuNPs). The photometer makes use of a single LED as a light source, a sensor TCS230 (TAOS, USA) and an Arduino electronic card as acquisition system. On the sensor, the light from the three closely-adjoined re...
The emergence of multi-resistant pathogens has catapulted research to new strategies to cope with this ever-increasing issue. In this context we combined silver nanoparticles (AgNPs) with doxycycline (DO, an antibiotic from the class of tetracyclines) to evaluate the potentiality of this hybrid as a bactericidal agent against E. coli. Polyvinylpyrr...
In this report we present new insights into the formation mechanism of Ag, Au and AgAu nanoparticles with alcohols, aldehydes and ketones in alkaline medium at room temperature. We selected methanol, ethanol, glycerol, formaldehyde, acetaldehyde and acetone to demonstrate their capability of reducing gold and silver ions under the above-mentioned c...
Bimetallic AuAg NPs (NPs) were synthesized via chemical reduction of AuCl3 and AgNO3 and fully characterized by several experimental techniques and theoretical calculations. The plasmon absorptions of these NPs were correlated with the most stable particle structure through different simulations, revealing the most stable structure to be consisted...
In this study we report a friendly route to produce colloidal AuAg bimetallic nanoparticles (NPs) using glycerol as reducing chemical in alkaline medium. Ultraviolet spectroscopy (UV-Vis) and transmission electron microscopy (TEM) confirmed the formation of colloidal NPs. The nanoparticles were also directly produced onto carbon to yield Au/C, Ag/C...
Stoichiometry has always been a puzzling subject. This may be partially due to the way it is introduced to students, with stoichiometric coefficients usually provided in the reaction. If the stoichiometric coefficients are not given, students find very difficult to solve problems. This article describes a simple 4-h laboratory experiment for the de...
Herein we demonstrate that LbL films comprising PAMAM dendrimers and single-walled carbon nanotubes (SWCNTs) are efficient for controlling the morphology of electrogenerated platinum-cobalt (PtCo) nanostructures. While Co grew to the micrometer scale and poorly covered the ITO substrate, with the LbL matrix it was kept in the nanoscale regime and p...
In this study we show, for the first time, that gold nanoparticles (AuNPs) synthesized by a simple, inexpensive, and environmentally-correct method can be easily conjugated with the antibodies anti-β-catenin and anti-E-cadherin to specifically target colorectal carcinoma cells. The antibody/AuNPs conjugates were then successfully applied for imagin...
In this paper we demonstrate that layer-by-layer (LbL) films of polyamidoamine (PAMAM) dendrimers and single-walled carbon nanotubes (SWCNTs) are efficient for controlling the morphology of electrogenerated cobalt (Co) and the platinum-cobalt (PtCo) alloy. While Co grew to the micrometer scale and poorly covered the ITO substrate, with the LbL matr...
Hybrid materials with enhanced properties can now be obtained by combining nanomaterials such as carbon nanotubes and metallic nanoparticles, where the main challenge is to control fabrication conditions. In this study, we demonstrate that platinum nanoparticles (PtNps) can be electrogenerated within layer-by-layer (LbL) films of polyamidoamine (PA...
Glycerol is at present abundantly co-produced in the biodiesel fabrication and can be used as fuel in Direct Glycerol Fuel Cells (DGFC) for cogeneration of electricity, value-added chemicals and heat. With this motivation, in the present work, we investigated at a fundamental level the oxidation of glycerol over glassy carbon (GC) supported Au nano...
In this work we evaluated the potentiality of a poly(imide) (PI)/organically-modified montmorillonite (O-MMT) nanocomposite membrane for the use in alkaline fuel cells. Both X-ray diffraction and scanning electron microscopy revealed a good dispersion of O-MMT into the PI matrix and preservation of the O-MMT layered structure. When compared to the...
In this paper we report a simple and environmentally friendly synthesis of gold nanoparticles (AuNps) and their electrocatalytic activity for borohydride oxidation reaction (BOR). Ultraviolet spectroscopy (UV–vis) and transmission electron microscopy (TEM) confirmed the formation of poly(vinyl pyrrolidone)-protected colloidal AuNps through direct r...
Magnetic and catalytic gold nanoparticles were electrodeposited through potential pulse on dendrimer–carbon nanotube layer-by-layer (LbL) films. A plasmon absorption band at about 550 nm revealed the presence of nanoscale gold in the film. The location of the Au nanoparticles in the film was clearly observed by selecting the magnetic force microsco...
In this paper we report a simple and environmentally friendly synthesis of silver nanoparticles (AgNps) and their activities towards the oxygen reduction reaction (ORR). Ultraviolet spectroscopy (UV–vis) and transmission electron microscopy confirmed the formation of poly(vinyl pyrrolidone)-protected colloidal AgNps through direct reduction of Ag+...
In the present paper we investigated the electrochemical behaviors of poly(vinyl pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) on Pt (111), (100) and (110) electrodes. Both polymers hampered the characteristic hydrogen UPD and anion adsorption/desorption on all investigated surfaces, with the processes on Pt(110) being the most affected by their...
In this paper we report the electrosynthesis of PVA-protected PtCo films (PVA = poly(vinylalcohol)) and their activities towards the oxygen reduction reaction (ORR). PtCo electrodeposits were potentiostatically obtained in the presence and absence of PVA at distinct potentials. The film morphology and composition were characterized by scanning elec...
PVA-protected Pt nanoparticles were electrochemically synthesized using hexachloroplatinic acid as a metal precursor and tested for methanol oxidation. Field emission gun microscopy (FEG) revealed that the absence of PVA allowed the Pt electrodeposit to grow to the micrometer regime, while its presence refined the grain size. The deposition time al...
In the present paper we investigated the electrochemical behavior of PVP on polycrystalline and single-crystal Pt electrodes. PVP hampered the characteristic hydrogen UPD and anion adsorption on all investigated surfaces. Several oxidation processes appeared in the anodic sweep with Pt(111) and Pt(100) being the most active for the oxidation proces...
We report about the use of different ionic liquids and catalyst materials in lithium-oxygen batteries. Different types of oxygen electrodes such as self-supporting oxygen electrodes and catalyst-coated separators were prepared by hot-pressing and spray-coating procedures, respectively. Porous carbon material such as Ketjen Black, binder material an...
This paper presents the fabrication of a nanothick Co-modified film electrochemically synthesized on layer-by-layer (LbL) struc-tures made with dendrimer polyamidoamine/carbon nanotubes (PAMAM/CNT), and its electrocatalytic properties toward H 2 O 2 reduction. Scanning electron microscopy indicated the formation of a homogeneous, 14 nm thick Co fil...
In the present study macroporous aluminium electrodes were made by template assisted electrodeposition from ionic liquids. Polystyrene (PS) spheres (diameter 600nm) were applied onto polished copper electrodes by immersion into an alcoholic suspension containing PS spheres. Al was deposited from the chloroaluminate ionic liquid [EMIm]Cl/AlCl3 (40/6...
In the present work we investigated the electrochemical behavior of PVA on polycrystalline Pt and single-crystal Pt electrodes. PVA hampered the characteristic hydrogen UPD and anion adsorption on all investigated surfaces, with the processes on Pt(110) being the most affected by the PVA presence. Several oxidation waves appeared as the potential w...
In this discussion paper we discuss our recent results on the electrodeposition of materials and in situ STM/AFM measurements which demonstrate that ionic liquids should not be regarded as neutral solvents which all have similar properties. In particular, we focus on differences in interfacial structure (solvation layers) on metal electrodes as a f...
In the present paper the underpotential deposition (UPD) of lithium on Au(111) from 0.5 mol L(-1) LiTFSA in the air- and water stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide, [Py(1,4)]TFSA, has been investigated by cyclic voltammetry (CV) and in situ scanning tunneling microscopy (STM). The pure [Py(1,4)]TFSA wa...
In the present paper the electrodeposition of Ga on Au(111) from 0.5molL−1 GaCl3 in the air- and water-stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide, [Py1,4]TFSA, has been investigated by in situ scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and...
The surface interaction of two air- and water-stable ionic liquids (ILs), 1-ethyl-3-methylimidazolium bis[(trifluoromethylsulfonyl]amide ([EMIm]TFSA) and 1-butyl-1-methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]amide ([BMP]TFSA), with Au(111) has been investigated using atomic force microscopy (AFM), cyclic voltammetry, and scanning tunneling mi...
The use of carbon nanotubes (CNTs) combined with other materials in nanostructured films has demonstrated their versatility in tailoring specific properties. In this study, we produced layer-by-layer (LbL) films of polyamidoamine-PAMAM-incorporating multiwalled carbon nanotubes (PAMAM-NT) alternated with nickel tetrasulfonated metallophthalocyanine...
The response surface methodology was used to find the optimal condition for electrolytic Pb(II) removal by using, as the experimental
design, a central composite rotatable design for two variables (current and flow rate) at five levels. The surfaces generated
with the second-order-equation fitted data showed the positive influence of increasing the...
Electroactive nanostructured films of chitosan (Ch) and tetrasulfonated metallophthalocyanines containing nickel (NiTsPc), copper (CuTsPc), and iron (FeTsPc) were produced via the electrostatic layer-by-layer (LbL) technique. The multilayer formation was monitored with UV-vis spectroscopy by measuring the increase of the Q-band absorption from meta...
The investigation of an electrolytic process to remove Pb(II) from simulated wastewaters using a stainless-steel wool (SSW) cathode in a flow-through cell under potentiostatic condition is reported. Voltammetry under hydrodynamic conditions was used to estimate the diffusion coefficient, which was found to be 1.4 10−5cm2s−1 in the supporting electr...