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1.
Small ; 20(44): e2404268, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39011945

RESUMO

Active control of nanotribological properties is a challenge. Materials responsive to external stimuli may catalyze this paradigm shift. Recently, the nanofriction of a thin film is modulated by light, ushering in phototribology. This frontier is expanded here, by investigating photoactive nanoparticles in lubricants to confer similar functionality to passive surfaces. Quartz-crystal microbalance (QCM) is employed to assess the phototribological behavior of aqueous suspensions of titanium dioxide nanoparticles. A comparison of dark and illuminated conditions provides the first demonstration of tuning the interfacial friction in solid-nanosuspension interfaces by light. Cyclic tests reveal reversible transitions between higher (dark) and lower friction (illuminated) regimes. These transitions are underpinned by transient states with surface charge variations, as confirmed by Zeta potential measurements. The accumulated surface charge increases repulsion within the system and favors sliding. Upon cessation of illumination, the system returns to its prior equilibrium state. These findings impact not only nanotribology but nanofluidics and nanorheology. Furthermore, the results underscore the need to consider light-induced effects in other scenarios, including the calculation of activity coefficients of photoactive suspensions. This multifaceted study introduces a new dimension to in operando frictional tuning, beckoning a myriad of applications and fundamental insights at the nanoscale.

2.
Phys Chem Chem Phys ; 26(40): 25748-25761, 2024 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-39361027

RESUMO

Electrochemical impedance spectroscopy (EIS) is a powerful technique that can be used to investigate the properties of materials, interfaces, and their redox reactions. It is applied to describe electrochemical systems and support the development of important technologies, offering a much more detailed investigation of properties than other conventional electrochemical techniques. EIS employs a modulated frequency to understand frequency-dependent electrochemical processes, thereby clarifying both fast and slow processes. As a dynamic and robust tool, a thorough understanding of this technique allows the precise use of the information it provides. In this review, we cover the history of the technique's development, its fundamental theory, and necessary conditions for proper use, in addition to providing guidelines on how to use EIS for data collection and the acquisition of relevant information provided by the technique. We also discuss complications related to the necessary conditions, equivalent circuits used for describing systems, commonly used plots, the configuration of electrochemical cells and the possibilities for the use and application of EIS techniques to characterize supercapacitors and batteries. This paper provides meaningful information and discussion related to EIS and ways to better utilize it for investigating the properties of materials.

3.
Chemphyschem ; 24(21): e202300002, 2023 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-37535823

RESUMO

Environmentally friendly methods for silver nanoparticles (AgNPs) synthesis without the use of hazardous chemicals have recently drawn attention. In this work, AgNPs have been synthesized by microwave irradiation using only honey solutions or aqueous fresh pink radish extracts. The concentrations of honey, radish extract, AgNO3 and pH were varied. AgNPs presented mean sizes between 7.0 and 12.8 nm and were stable up to 120 days. The AgNPs were employed as co-catalyst (TiO2 @AgNPs) to increase the hydrogen photogeneration under UV-vis and only visible light irradiation, when compared to pristine TiO2 NPs. The prepared photocatalyst also showed hydrogen generation under visible light. Additionally, AgNPs were used to assemble a nanoplasmonic biosensor for the biodetection of extremely low concentrations of streptavidin, owing to its specific binding to biotin. It is shown here that green AgNPs are versatile nanomaterials, thus being potential candidates for hydrogen photogeneration and biosensing applications.


Assuntos
Nanopartículas Metálicas , Prata , Extratos Vegetais , Escherichia coli , Antibacterianos
4.
J Digit Imaging ; 36(3): 1060-1070, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36650299

RESUMO

Artificial neural networks (ANN) are artificial intelligence (AI) techniques used in the automated recognition and classification of pathological changes from clinical images in areas such as ophthalmology, dermatology, and oral medicine. The combination of enterprise imaging and AI is gaining notoriety for its potential benefits in healthcare areas such as cardiology, dermatology, ophthalmology, pathology, physiatry, radiation oncology, radiology, and endoscopic. The present study aimed to analyze, through a systematic literature review, the application of performance of ANN and deep learning in the recognition and automated classification of lesions from clinical images, when comparing to the human performance. The PRISMA 2020 approach (Preferred Reporting Items for Systematic Reviews and Meta-analyses) was used by searching four databases of studies that reference the use of IA to define the diagnosis of lesions in ophthalmology, dermatology, and oral medicine areas. A quantitative and qualitative analyses of the articles that met the inclusion criteria were performed. The search yielded the inclusion of 60 studies. It was found that the interest in the topic has increased, especially in the last 3 years. We observed that the performance of IA models is promising, with high accuracy, sensitivity, and specificity, most of them had outcomes equivalent to human comparators. The reproducibility of the performance of models in real-life practice has been reported as a critical point. Study designs and results have been progressively improved. IA resources have the potential to contribute to several areas of health. In the coming years, it is likely to be incorporated into everyday life, contributing to the precision and reducing the time required by the diagnostic process.


Assuntos
Dermatologia , Oftalmologia , Humanos , Inteligência Artificial , Reprodutibilidade dos Testes , Redes Neurais de Computação
5.
Int J Mol Sci ; 23(22)2022 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-36430525

RESUMO

Titanium is usually used in the manufacturing of metal implants due to its biocompatibility and high resistance to corrosion. A structural and functional connection between the living bone and the surface of the implant, a process called osseointegration, is mandatory for avoiding prolonged healing, infections, and tissue loss. Therefore, osseointegration is crucial for the success of the implantation procedure. Osseointegration is a process mediated by bone-matrix progenitor cells' proteins, named integrins. In this study, we used an in silico approach to assemble and test peptides that can be strategically used in sensitizing TiO2 implants in order to improve osseointegration. To do so, we downloaded PDB structures of integrins α5ß1, αvß3, and αIIbß3; their biological ligands; and low-cost proteins from the Protein Data Bank, and then we performed a primary (integrin-protein) docking analysis. Furthermore, we modeled complex peptides with the potential to bind to the TiO2 surface on the implant, as well as integrins in the bone-matrix progenitor cells. Then we performed a secondary (integrin-peptide) docking analysis. The ten most promising integrin-peptide docking results were further verified by molecular dynamics (MD) simulations. We recognized 82 peptides with great potential to bind the integrins, and therefore to be used in coating TiO2 implants. Among them, peptides 1 (GHTHYHAVRTQTTGR), 3 (RKLPDATGR), and 8 (GHTHYHAVRTQTLKA) showed the highest binding stability during the MD simulations. This bioinformatics approach saves time and more effectively directs in vitro studies.


Assuntos
Materiais Revestidos Biocompatíveis , Titânio , Materiais Revestidos Biocompatíveis/química , Titânio/farmacologia , Titânio/química , Peptídeos , Integrinas
6.
An Acad Bras Cienc ; 92(3): e20200504, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33111823

RESUMO

The development of stable and active TiO2 nanotubes (NTs) decorated with plasmonic gold nanoparticles (Au NPs) represents a strategy for charge-transfer processes improvements. However, organic capping ligands used for Au NPs synthesis usually remain on the surface of the metal, leading to poor Schottky junctions between Au and TiO2. Herein, we report on the synthesis of a nanotubular matrix of TiO2 decorated with gold without the need of ligands. The Au NPs mean diameter (12 nm) was similar to all the samples prepared, no matter the metal loading. Such materials enabled to use the metal as a cocatalyst for photogeneration of H2under UV and visible light irradiations. We found an optimum metal loading (2.6 wt% Au) that enabled an improvement of 760% on the H2 production when compared to the bare TiO2 NTs under UV-Vis irradiation. In addition, such catalyst was able to perform photogeneration of H2 under visible irradiation, which was not conceivable before the metal immobilization over the TiO2 NTs. The yield obtained was comparable to the observed when the catalyst was used under UV-Vis conditions. The produced materials were fully characterized by UV-Vis, XRD, TEM, and SEM.

7.
Nanotechnology ; 30(6): 065604, 2019 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-30523846

RESUMO

Anatase nanotubes with high surface area (ca. 350 m2 g-1), containing gold nanoparticles, were successfully obtained from trititanate nanotubes, prepared by a template-free hydrothermal method, and calcined at 450 °C. The high surface area and tubular morphology were attained due to the presence of ionic silsesquioxane, which acts as anti-sintering agent for titania during calcination process, by forming a thin silica coating between anatase nanotubes. Additionally, the ionic silsesquioxane also acts as stabilizing and adhesion agent for gold nanoparticles on the surface of anatase nanotubes. The influence of the ionic silsesquioxane on the morphological and textural properties of anatase nanotubes was studied in three different moments during the synthesis: before, after and before/after nanotubes were rolled up. The photocatalytic activity of the nanotube samples was evaluated by hydrogen generation showing remarkable enhancement in hydrogen production and stability of catalyst when compare with the bare anatase sample and commercial P-25.

8.
Nanotechnology ; 28(11): 115603, 2017 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-28192283

RESUMO

The thermal decomposition (TD) methods are among the most successful in obtaining magnetic nanoparticles with a high degree of control of size and narrow particle size distribution. Here we investigated the TD of iron(III) acetylacetonate in the presence of oleic acid, oleylamine, and a series of alcohols in order to disclose their role and also investigate economically attractive alternatives for the synthesis of iron oxide nanoparticles without compromising their size and shape control. We have found that some affordable and reasonably less priced alcohols, such as 1,2-octanediol and cyclohexanol, may replace the commonly used and expensive 1,2-hexadecanediol, providing an economically attractive route for the synthesis of high quality magnetic nanoparticles. The relative cost for the preparation of Fe3O4 NPs is reduced to only 21% and 9% of the original cost when using 1,2-octanediol and cyclohexanol, respectively.

9.
Nanotechnology ; 27(28): 285401, 2016 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-27251109

RESUMO

Hydrogen fuels generated by water splitting using a photocatalyst and solar irradiation are currently gaining the strength to diversify the world energy matrix in a green way. CdS quantum dots have revealed a hydrogen generation improvement when added to TiO2 materials under visible-light irradiation. In the present paper, we investigated the performance of TiO2 nanotubes coupled with CdS quantum dots, by a molecular bifunctional linker, on photocatalytic hydrogen generation. TiO2 nanotubes were obtained by anodization of Ti foil, followed by annealing to crystallize the nanotubes into the anatase phase. Afterwards, the samples were sensitized with CdS quantum dots via an in situ hydrothermal route using 3-mercaptopropionic acid as the capping agent. This sensitization technique permits high loading and uniform distribution of CdS quantum dots onto TiO2 nanotubes. The XPS depth profile showed that CdS concentration remains almost unchanged (homogeneous), while the concentration relative to the sulfate anion decreases by more than 80% with respect to the initial value after ∼100 nm in depth. The presence of sulfate anions is due to the oxidation of sulfide and occurs in greater proportion in the material surface. This protection for air oxidation inside the nanotubular matrix seemingly protected the CdS for photocorrosion in sacrificial solution leading to good stability properties proved by long duration, stable photocurrent measurements. The effect of the size and the distribution of sizes of CdS quantum dots attached to TiO2 nanotubes on the photocatalytic hydrogen generation were investigated. The experimental results showed three different behaviors when the reaction time of CdS synthesis was increased in the sensitized samples, i.e. similar, deactivation and activation effects on the hydrogen production with regard to TiO2 nanotubes. The deactivation effect was related to two populations of sizes of CdS, where the population with a shorter band gap acts as a trap for the electrons photogenerated by the population with a larger band gap. Electron transfer from CdS quantum dots to TiO2 semiconductor nanotubes was proven by the results of UPS measurements combined with optical band gap measurements. This property facilitates an improvement of the visible-light hydrogen evolution rate from zero, for TiO2 nanotubes, to approximately 0.3 µmol cm(-2) h(-1) for TiO2 nanotubes sensitized with CdS quantum dots.

10.
ChemSusChem ; 17(2): e202300884, 2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-37707501

RESUMO

Climate change and the demand for clean energy have challenged scientists worldwide to produce/store more energy to reduce carbon emissions. This work proposes a conductive gel biopolymer electrolyte to support the sustainable development of high-power aqueous supercapacitors. The gel uses saline water and seaweed as sustainable resources. Herein, a biopolymer agar-agar, extracted from red algae, is modified to increase gel viscosity up to 17-fold. This occurs due to alkaline treatment and an increase in the concentration of the agar-agar biopolymer, resulting in a strengthened gel with cohesive superfibres. The thermal degradation and agar modification mechanisms are explored. The electrolyte is applied to manufacture sustainable and flexible supercapacitors with satisfactory energy density (0.764 Wh kg-1 ) and power density (230 W kg-1 ). As an electrolyte, the aqueous gel promotes a long device cycle life (3500 cycles) for 1 A g-1 , showing good transport properties and low cost of acquisition and enabling the supercapacitor to be manufactured outside a glove box. These features decrease the cost of production and favor scale-up. To this end, this work provides eco-friendly electrolytes for the next generation of flexible energy storage devices.

11.
Artigo em Inglês | MEDLINE | ID: mdl-38161085

RESUMO

OBJECTIVE: This retrospective study analyzed the errors generated by a convolutional neural network (CNN) when performing automated classification of oral lesions according to their clinical characteristics, seeking to identify patterns in systemic errors in the intermediate layers of the CNN. STUDY DESIGN: A cross-sectional analysis nested in a previous trial in which automated classification by a CNN model of elementary lesions from clinical images of oral lesions was performed. The resulting CNN classification errors formed the dataset for this study. A total of 116 real outputs were identified that diverged from the estimated outputs, representing 7.6% of the total images analyzed by the CNN. RESULTS: The discrepancies between the real and estimated outputs were associated with problems relating to image sharpness, resolution, and focus; human errors; and the impact of data augmentation. CONCLUSIONS: From qualitative analysis of errors in the process of automated classification of clinical images, it was possible to confirm the impact of image quality, as well as identify the strong impact of the data augmentation process. Knowledge of the factors that models evaluate to make decisions can increase confidence in the high classification potential of CNNs.


Assuntos
Redes Neurais de Computação , Humanos , Estudos Transversais , Estudos Retrospectivos
12.
ACS Omega ; 9(37): 39100-39118, 2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39310144

RESUMO

Nanoemulsions are dispersions of oil-in-water (O/W) and water-in-oil (W/O) immiscible liquids. Thus, our main goal was to formulate a nanoemulsion with low surfactant concentrations and outstanding stability using Copaiba balsam oil (Copaifera sp.). The high-energy cavitation homogenization with low Tween 80 levels was employed. Then, electrophoretic and physical mobility properties were assessed, in addition to a one- and two-year physicochemical characterization studies assessment. Copaiba balsam oil and nanoemulsions obtained caryophyllene as a major constituent. The nanoemulsions stored at 4 ± 2 °C exhibited better physical stability. Two years after formulation, the nanoemulsion showed a reduction in the particle size. The size underwent changes in gastric, intestinal, and blood pH, and the PdI was not changed. In FTIR, characteristic bands of sesquiterpenes and overlapping bands were detected. When subjected to freezing and heating cycles, nanoemulsions did not show macroscopic changes in higher concentrations. Nanoemulsions subjected to centrifuge force by 1000 rpm do not show macroscopic instability and phase inversion or destabilization characteristics when diluted. Therefore, the nanoemulsion showed stability for long-term storage. The nematode Caenorhabditis elegans was used to assess the potential toxicity of nanoemulsions. The nanoemulsion did not cause toxicity in the animal model, except in the highest concentration tested, which decreased the defecation cycle interval and body length. The toxicity and stability outcomes reinforce the nanoemulsions' potential for future studies to explore pharmacological mechanisms in superior experimental designs.

13.
Artigo em Inglês | MEDLINE | ID: mdl-36900902

RESUMO

OBJECTIVES: Artificial intelligence has generated a significant impact in the health field. The aim of this study was to perform the training and validation of a convolutional neural network (CNN)-based model to automatically classify six clinical representation categories of oral lesion images. METHOD: The CNN model was developed with the objective of automatically classifying the images into six categories of elementary lesions: (1) papule/nodule; (2) macule/spot; (3) vesicle/bullous; (4) erosion; (5) ulcer and (6) plaque. We selected four architectures and using our dataset we decided to test the following architectures: ResNet-50, VGG16, InceptionV3 and Xception. We used the confusion matrix as the main metric for the CNN evaluation and discussion. RESULTS: A total of 5069 images of oral mucosa lesions were used. The oral elementary lesions classification reached the best result using an architecture based on InceptionV3. After hyperparameter optimization, we reached more than 71% correct predictions in all six lesion classes. The classification achieved an average accuracy of 95.09% in our dataset. CONCLUSIONS: We reported the development of an artificial intelligence model for the automated classification of elementary lesions from oral clinical images, achieving satisfactory performance. Future directions include the study of including trained layers to establish patterns of characteristics that determine benign, potentially malignant and malignant lesions.


Assuntos
Inteligência Artificial , Redes Neurais de Computação
14.
Materials (Basel) ; 15(9)2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35591484

RESUMO

This review addresses the different aspects of the use of titanium and its alloys in the production of dental implants, the most common causes of implant failures and the development of improved surfaces capable of stimulating osseointegration and guaranteeing the long-term success of dental implants. Titanium is the main material for the development of dental implants; despite this, different surface modifications are studied aiming to improve the osseointegration process. Nanoscale modifications and the bioactivation of surfaces with biological molecules can promote faster healing when compared to smooth surfaces. Recent studies have also pointed out that gradual changes in the implant, based on the microenvironment of insertion, are factors that may improve the integration of the implant with soft and bone tissues, preventing infections and osseointegration failures. In this context, the understanding that nanobiotechnological surface modifications in titanium dental implants improve the osseointegration process arouses interest in the development of new strategies, which is a highly relevant factor in the production of improved dental materials.

15.
Talanta ; 243: 123355, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35272155

RESUMO

Mass testing for the diagnosis of COVID-19 has been hampered in many countries owing to the high cost of genetic material detection. This study reports on a low-cost immunoassay for detecting SARS-CoV-2 within 30 min using dynamic light scattering (DLS). The immunosensor comprises 50-nm gold nanoparticles (AuNPs) functionalized with antibodies against SARS-CoV-2 spike glycoprotein, whose bioconjugation was confirmed using transmission electron microscopy (TEM), UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and surface-enhanced Raman scattering spectroscopy (SERS). The specific binding of the bioconjugates to the spike protein led to an increase in bioconjugate size, with a limit of detection (LOD) 5.29 × 103 TCID50/mL (Tissue Culture Infectious Dose). The immunosensor was also proven to be selective upon interaction with influenza viruses once no increase in size was observed after DLS measurement. The strategy proposed here aimed to use antibodies conjugated to AuNPs as a generic platform that can be extended to other detection principles, enabling technologies for low-cost mass testing for COVID-19.


Assuntos
Técnicas Biossensoriais , COVID-19 , Nanopartículas Metálicas , Técnicas Biossensoriais/métodos , COVID-19/diagnóstico , Teste para COVID-19 , Difusão Dinâmica da Luz , Ouro/química , Humanos , Imunoensaio/métodos , Nanopartículas Metálicas/química , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Proteínas Virais
16.
Phys Chem Chem Phys ; 13(30): 13552-7, 2011 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-21731950

RESUMO

Sputtering deposition of gold onto the 1-(butyronitrile)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BCN)MI·N(Tf)(2) ionic liquid (IL) has generated colloidal and stable gold nanospheres (AuNS) and gold nanodisks (AuND) in a bimodal size distribution. Upon increasing the sputtering discharge voltage, three distinct phenomena were observed: (i) the mean diameter of both AuNS and AuND decreased; (ii) the population with lower diameters increased and (iii) the formation of AuND disappeared at voltages higher than 340 V. By dissolving the colloidal gold nanoparticles (AuNPs) in isopropanol and dropping the product onto carbon-coated Cu grids, 2D and 3D superlattices tended to be formed, as observed by transmission electron microscopy (TEM). Therefore, the formation of AuND is probably related to a strong interaction between sputtered Au atoms of low kinetic energy and the nitrile groups orientated to the vacuum phase of the IL surface, which drives the preferential anisotropic lateral growth.

17.
Biomolecules ; 11(12)2021 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-34944393

RESUMO

Titanium and its alloys are used as biomaterials for medical and dental applications, due to their mechanical and physical properties. Surface modifications of titanium with bioactive molecules can increase the osseointegration by improving the interface between the bone and implant. In this work, titanium dioxide nanotubes (TiO2NTs) were functionalized with a lectin from the plasma of the fish Oreochromis niloticus aiming to favor the adhesion and proliferation of osteoblast-like cells, improving its biocompatibility. The TiO2NTs were obtained by anodization of titanium and annealed at 400 °C for 3 h. The resulting TiO2NTs were characterized by high-resolution scanning electron microscopy. The successful incorporation of OniL on the surface of TiO2NTs, by spin coating, was demonstrated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIE), and attenuated total reflection-Fourier transform infrared spectrum (ATR-FTIR). Our results showed that TiO2NTs were successfully synthesized in a regular and well-distributed way. The modification of TiO2NTs with OniL favored adhesion, proliferation, and the osteogenic activity of osteoblast-like cells, suggesting its use to improve the quality and biocompatibility of titanium-based biomaterials.


Assuntos
Ciclídeos/metabolismo , Lectinas/química , Osteoblastos/citologia , Titânio/farmacologia , Ligas , Animais , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Espectroscopia Dielétrica , Microscopia Eletrônica de Varredura , Nanotubos , Osteogênese , Propriedades de Superfície , Titânio/química
18.
Phys Chem Chem Phys ; 12(25): 6826-33, 2010 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-20454725

RESUMO

Hydrogen reduction of cationic or neutral Ir(i) compounds, namely [Ir(COD)(2)]BF(4) and [Ir(COD)Cl](2)respectively. in the ionic liquid (IL) 1-alkyl-3-methylimidazolium tetrafluoroborate affords either irregularly sized spherical (from 1.9 +/- 0.4 to 3.6 +/- 0.9 nm) or worm-like metal nanoparticles, depending on the nature of the imidazolium alkyl group and the type of iridium precursor. The ionic Ir(i) precursor tends to be dissolved and concentrated on the IL polar domains (populated by the imidazolium nucleus and tetrafluoroborate anions) while the neutral precursor dissolves preferentially in the non-polar region of the IL (populated mainly by N-alkyl side chains). The size, or volume, of the nano-region where the Ir(i) precursor is dissolved and reduced, determines the size and, probably, the shape of the formed nanoparticles. The HR-TEM image shows that the Ir(0) with worm-like shape are polycrystalline and formed from aggregation individual "spherical" nanoparticles of around 1.9 nm. The catalytic activity of Ir(0) NPs on the hydrogenation of cyclohexene (0.01 mol L(-1) of Ir atoms in IL, 75 degrees C, 8 bar of H(2), 500 rpm stirring, 1/1000 Ir(0)/cyclohexene ratio) is always greater in C(1)C(10)I.BF(4) than C(1)C(4)I.BF(4), regardless of the nature of Ir(i) precursor. Moreover, the cyclohexene hydrogenations performed with Ir(0) nanocatalysts made from ionic Ir(i) precursor are approximately twice faster than those NPs obtained from the neutral Ir(i) precursor, in the same IL.

19.
Mater Sci Eng C Mater Biol Appl ; 108: 110194, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31923931

RESUMO

The thermal, physical, and morphological properties of diphenhydraminium ibuprofenate ([DIP][IBU]) adsorbed onto mesoporous silica (SiO2-60 Šand SiO2-90 Å) from solution were determined. The thermal, physical, and morphological properties of [DIP][IBU] supported on silica were determined. The adsorption of [DIP][IBU] on the pores and surface of silica was proven by N2 adsorption/desorption isotherms. Additionally, release profiles were determined for all systems, and the antinociceptive activity of neat [DIP][IBU] and [DIP][IBU] supported on silica were determined. The interaction of [DIP][IBU] and silica was dependent on pore size, with the formation of a [DIP][IBU] monolayer on SiO2-60 and a multilayer on SiO2-90. The release profile was sustained and slow and dependent on the pore size of the silica, in which the smaller the pore size, the faster the release. The nociceptive evaluation showed that [DIP][IBU] presents a greater (99.21 ±â€¯0.85%) antinociceptive effect than the ibuprofen (46 ±â€¯4.3%). Additionally, [DIP][IBU] on SiO2-60 (90 ±â€¯5.8%) had a greater antinociceptive effect than on SiO2-90 (73 ±â€¯13.2%), which indicates that in vivo tests are in accordance with the in vitro experiments.


Assuntos
Analgésicos , Ibuprofeno , Dor/tratamento farmacológico , Dióxido de Silício , Analgésicos/química , Analgésicos/farmacocinética , Analgésicos/farmacologia , Animais , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Preparações de Ação Retardada/farmacologia , Avaliação Pré-Clínica de Medicamentos , Ibuprofeno/análogos & derivados , Ibuprofeno/química , Ibuprofeno/farmacocinética , Ibuprofeno/farmacologia , Masculino , Camundongos , Dor/metabolismo , Dor/fisiopatologia , Porosidade , Dióxido de Silício/química , Dióxido de Silício/farmacocinética , Dióxido de Silício/farmacologia
20.
Sci Total Environ ; 660: 459-467, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30640113

RESUMO

The use of silver nanoparticles (AgNPs) in commercial products has increased significantly in recent years. However, findings on the toxic effects of the AgNPs are still limited. This paper reports an investigation on the cytotoxic and genotoxic potential of the AgNPs on root cells of Allium cepa. Germination (GI), root elongation (REI), mitotic (MI), nuclear abnormality (NAI), and micronucleus index (MNI) were determined for seeds exposed to various AgNPs diameters (10, 20, 51, and 73 nm) as well as to the silver bulk (AgBulk) (micrometer-size particles) at the concentration of 100 mg·L-1. Transmission electron microscopy (TEM) provided the particle size distribution, while dynamic light scattering (DLS) was used to get the hydrodynamic size, polydispersity index, and zeta potential of the AgNPs. Laser-induced breakdown spectroscopy (LIBS) and inductively coupled plasma/optical emission spectrometry (ICP OES) were applied for quantifying the AgNPs content uptake by roots. Silver dissolution was determined by dialysis experiment. Results showed that the AgNPs penetrated the roots, affecting MI, GI, NAI, and MNI in meristematic cells. Changes in these indicators were AgNPs diameter-dependent so that cytotoxic and genotoxic effects in Allium cepa increased with the reduction of the particle diameter. The results also revealed that the AgNPs were the main responsible for the cytotoxicity and genotoxicity since negligible silver dissolution was observed.


Assuntos
Allium/efeitos dos fármacos , Citotoxinas/efeitos adversos , Meristema/efeitos dos fármacos , Nanopartículas Metálicas/efeitos adversos , Mutagênicos/efeitos adversos , Prata/efeitos adversos , Testes de Mutagenicidade , Tamanho da Partícula , Raízes de Plantas/efeitos dos fármacos , Células-Tronco/efeitos dos fármacos
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