Influência da superfície do titânio nitretado a plasma em diferentes atmosferas na ativação de plaquetas sanguíneas

This study aimed to analyze the biological response of titanium surfaces modified by plasma Ar + N2 + H2. Titanium disks grade II received different surface treatments Ar + N2 + H2 plasma, constituting seven groups including only polished samples used as standard. Before and after treatment the samples were evaluated in terms of topography, crystal structure and wettability, using atomic force microscopy, X-ray diffraction, Raman spectroscopy and testing of the sessile drop, respectively. Rich plasma (PRP) was applied to the surfaces modified in culture plates. Images obtained by scanning electron microscopy of the adhered platelets were analyzed to verify the behavior of platelets in the different experimental conditions. We verified that the adition of H2 on plasma atmosphere resulted in more rough surfaces, with round tops. These surfaces, in contrast to that surfaces treated with high concentration of N2, are less propense to platelet aggregation and, consequently, to the formation of thrombus when applied in biomedical devices.

Influência das espécies do plasma de N2 + O2 nas propriedades físicoquímicas das superfícies do pet

This work reports the influence of the poly (ethylene terephthalate) textile and films surface modification by plasmas of O2 and mixtures (N2 + O2), on their physical and chemical properties. The plasma surface polymeric modification has been used for many researchs, because it does not affect the environment with toxic agents, the alterations remains only at nanometric layers and this technique shows expressive results. Then, due to its good acceptance, the treatment was carried out in a vacuum chamber. Some parameters remained constant during all treatment, such as: Voltage 470 V; Pressure 1,250 Mbar; Current: 0, 10 A and gas flow: 10 cm3/min, using oxygen plasma alternating the treatment time 10 to 60 min with an increase of 10 min to each subsequent treatment. Also, the samples were treated with a gas mixture (nitrogen + oxygen) which was varied only the gas composition from 0 to 100% leaving the treatment time remaining constant to all treatment (10 min). The plasma treatment was characterized in-situ with Optics Emission Spectroscopy (OES), and the samples was characterized by contact angle, surface tension, Through Capillary tests, Raman spectroscopy, Infrared attenuated total reflection (IR-ATR) and atomic force microscopy, scanning electronic Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The results showed that oxygen treated fabrics presented high wettability, due to the hydrophilic groups incorporation onto the surface formed through spputering of carbon atoms. For the nitrogen atmosphere, there is the a film deposition of amine groups. Treatment with small oxygen concentration in the mixture with nitrogen has a higher spputered species of the samples

Estudo da adesão de pinos endodônticos modificados superficialmente por plasma de oxigênio

The work presents the effect of plasma treatment when applied in fibers or carbon/glass posts in the adhesion fiber/resin and posts/cement. This has for objective the modification of the surface of the fibers, as well as the wettability of the posts, seeking the improvement of the adhesion and of the connection fiber/resin in the processing of polymeric composites reinforced with the same ones. 120 posts (Reforpost) were used and 30 meters of fibers of carbon and of glass (Fibrex), of the company Angelus. The samples were divided in three groups of 40 specimens: GROUP I - 20 posts of glass fiber and 20 of carbon without treatment to it shapes, GROUP II -20 posts of glass fiber and 20 of carbon treated to it shapes in the surface and GROUP III - 20 posts of glass fiber and 20 of carbon make with fibers in natura after plasma treatment. The plasma treatment was accomplished with oxygen and with temperature in the camera fixed at 200°C, for one hour of exhibition. The posts and the fibers were characterized before and after the treatment. The wettability was measure by pendent drop method, and interface fiber/resin and posts/cement were observed by optical and electronic microscopy. It was observed that both wettability and texture were increased with plasma treatment

Modificação de membranas de quitosana por plasma para uso biológico

Chitosan membranes have been modified by plasma, utilizing the following gases: nitrogen (N2), methane (CH4), argon (Ar), oxygen (O2) and hydrogen. The modified membranes by plasma were compared to the unmodified ones. The membranes were characterized by absorption assay, contact angle, atomic force microscopy (AFM). Also, permeability assay of sodium sulfamerazine from such membranes were carried out. Through the absorption assay and contact angle it was possible to obtain information of the wettability of the membranes and what changes the plasma treatment can promote in relation to it. The plasma treatment using oxygen promoted increase of the wetability and swelling while the samples treated with methane decrease of the wetability and swelling. Through the Optical Emission Spectroscopy (OES) it was possible to identify which species were present in the plasma during the treatment. And through the AFM analysis it was possible to observe the changes nanotopography occurred on the surface of the samples. Permeability assay were archived for all treated membranes and compared to no treated ones. Due to that assay it was possible verify which the plasma treatment increased the permeability spectrum of the membranes which has varied from 1,4548 *10-5cm2.min-1 to 2,7713*10-5cm2.min-1. Chitosan membranes with permeability varied are importance in systems drug delivery, to liberate a wide variety of drugs

Tratamento termoquímico do titânio auxiliado por plasma de ar - N2 - O2

Discs were grade II cp Ti oxynitride by plasma of Ar - N2 - O2 using different proportions of individual gases. These ratios were established from analysis of optical emission spectroscopy (OES) of plasma species. The proportions that resulted in species whose spectra showed an abrupt change of light intensity were chosen for this study. Nanohardness tests revealed that there was a correlation between the intensity of N2 + species with the hardness, because the treatments where they had a higher intensity, obtained a higher value nanohardness, although the crystalline phases have remained unchanged. With respect to topography, it was observed that in general, the surface roughness is related to the intensities of plasma species, because they may have different values depending on the behavior of the species. Images obtained by optical microscopy revealed a surface with grains of different colors to optical reflectance showed a peak of reflection in the red area. Measures the contact angle and surface tension showed hydrophilic properties and hydrophilic with little variation of polar and dispersive components of surface tension

Influência das espécies ativas na absorção de intersticiais durante a carbonitretação a plasma do TI

Physical-chemical properties of Ti are sensible to the presence of interstitial elements. In the case of thermochemical treatments plasma assisted, the influence of different active species is not still understood. In order to contribute for such knowledge, this work purposes a study of the role played by the active species atmosphere into the Ar N2 CH4 carbonitriding plasma. It was carried out a plasma diagnostic by OES (Optical Emission Spectroscopy) in the z Ar y N2 x CH4 plasma mixture, in which z, y and x indexes represent gas flow variable from 0 to 4 sccm (cm3/min). The diagnostic presents abrupt variations of emission intensities associated to the species in determined conditions. Therefore, they were selected in order to carry out the chemical treatment and then to investigate their influences. Commercial pure Ti disks were submitted to plasma carbonitriding process using pre-established conditions from the OES measurements while some parameters such as pressure and temperature were maintained constant. The concentration profiles of interstitial elements (C and N atoms) were determined by Resonant Nuclear Reaction Analysis (NRA) resulting in a depth profile plots. The reactions used were 15N(ρ,αγ)12C and 12C(α,α)12C. GIXRD (Grazing Incidence X-Ray Diffraction) analysis was used in order to identify the presence of phases on the surface. Micro-Raman spectroscopy was used in order to qualitatively study the carbon into the TiCxN1 structure. It has been verified which the density species effectively influences more the diffusion of particles into the Ti lattice and characteristics of the layer formed than the gas concentration. High intensity of N2 + (391,4 nm) and CH (387,1 nm) species promotes more diffusion of C and N. It was observed that Hα (656,3 nm) species acts like a catalyzer allowing a deeper diffusion of nitrogen and carbon into the titanium lattice.

Diagnóstico das espécies ativas do plasma usado em tratamentos termoquímicos do titânio

Plasma diagnostics by Optical Emission Spectroscopy were performed for electrical discharge in three gas mixture respecting the combinations z N2 y Ar x H2, z N2 y Ar x O2 e z N2 y Ar x CH4, in which the indexes z and y systematically vary from 1 to 4 and x varies from 0 to 4, every one has dimension SCCM, resulting in 80 combinations. From the all obtained spectrums, the species CH (387,1 nm), N2+ (391,4 nm), Hβ (486,1 nm), Hα (656,3 nm), Ar (750,4 nm), O (777,4 nm) e O (842,6 nm) were analyzed because of their abundance and importance on the kinetic of reaction from the plasma to surface, besides their high dependences on the gases flows. Particularly interesting z, y and x combinations were chosen in order to study the influence of active species on the surface modification during the thermochemical treatment. From the mixtures N2 Ar O2 e N2 Ar CH4 were chosen three peculiar proportions which presented luminous intensity profile with unexpected maximum or minimum values, denominated as plasma anomaly. Those plasma concentrations were utilized as atmosphere of titanium treatment maintaining constant the control parameters pressure and temperature. It has been verified a relation among luminous intensity associated to N2+ and roughness, nanohardness and O atoms diffusion into the crystalline lattice of treated titanium and it has been seen which those properties becomes more intense precisely in the higher points found in the optical profile associated to the N2+ specie. Those parameters were verified for the mixture which involved O2 gas. For the mixture which involves CH4 gas, the relation was determinate by roughness, number of nitrogen and carbon atoms diffused into the titanium structure which presented direct proportionality with the luminous intensity referent to the N2+ and CH. It has been yet studied the formation of TiCN phases on the surface which presented to be essentially directly proportional to the increasing of the CH specie and inversely proportional to the increasing of the specie N2+

Efeito do tratamento por plasma na proliferação de fibroblastos e esterilização de membranas de quitosana

Chitosan is being studied for use as dressing due their biological properties. Aiming to expand the use in biomedical applications, chitosan membranes were modified by plasma using the following gases: nitrogen (N2), methane (CH4), argon (Ar), oxygen (O2) and hydrogen (H2). The samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle, surface energy and water absorption test. Biological Tests were also performed, such as: test sterilization and proliferation of fibroblasts (3T3 line). Through SEM we observed morphological changes occurring during the plasma treatment, the formation of micro and nano-sized valleys. MFA was used to analyze different roughness parameters (Ra, Rp, Rz) and surface topography. It was found that the treated samples had an increase in surface roughness and sharp peaks. Methane plasma treatment decreased the hydrophilicity of the membranes and also the rate of water absorption, while the other treatments turned the membranes hydrophilic. The sterilization was effective in all treatment times with the following gases: Ar, N2 and H2. With respect to proliferation, all treatments showed an improvement in cell proliferation increased in a range 150% to 250% compared to untreated membrane. The highlights were the treatments with Ar 60 min, O2 60 min, CH4 15 min. Observing the results of the analyzes performed in this study, it appears that there is no single parameter that influences cell proliferation, but rather a set of ideal conditions that favor cell proliferation

Determinação do perfil térmico em amostras de aço AISI M35 imersas em plasma

The heat transfer between plasma and a solid occurs mostly due the radiation and the collision of the particles on the material surface, heating the material from the surface to the bulk. The thermal gradient inside the sample depends of the rate of particles collisions and thermal conductivity of the solid. In order to study that effect, samples of AISI M35 steel, with 9,5 mm X 3,0 mm (diameter X thickness) were quenched in resistive furnace and tempereds in plasma using the plane configuration and hollow cathode, working with pressures of 4 and 10 mbar respectively. Analyzing the samples microstructure and measuring the hardness along the transversal profile, it was possible to associate the tempered temperature evaluating indirectly the thermal profile. This relation was obtained by microstructural analyzes and through the hardness curve x tempered sample temperature in resistive furnace, using temperatures of 500, 550, 600, 650 and 700°C. The microstructural characterization of the samples was obtained by the scanning electron microscopy, optic microscopy and X-ray diffraction. It was verified that all samples treated in plasma presented a superficial layer, denominated affected shelling zone, wich was not present in the samples treated in resistive furnace. Moreover, the samples that presented larger thermal gradient were treated in hollow cathode with pressure of 4 mbar

Efeito antibacteriano de tecidos têxteis revestidos por prata através da técnica de deposição por plasma

In this study, it has been investigated the influence of silver film deposition onto 100% polyester woven and non-woven, on the survival of Escherichia coli and Staphylococcus aureus in contact with these surfaces. The treatment was performedin a chamber containing the working gas at low pressure (~ 10-2 mbar). Some process parameters such as as voltage: 470 V; pressure: 10-2 mbar; current : 0.40 A and gas flow: 6 and 10 cm3/min were kept constant. For the treatments with purêargon plasma using a flow of 6 and 10 cm3/min, different treatment times were evaluated, such as, 10 , 20, 30, 40, 50 and 60 minutes. Contact angle (sessile drop), measurements were used to determine the surface tension of the treated fabrics and its influence on the bacteria grow as weel as the possibilities of a biofilm formation. The formation of a silver film, as well as the amount of this element was verified byEDX technique. The topography was observed through scanning electron microscopy (SEM) to determine the size of silver grains formed on the surfaces of the fabric and assess homogeneity of treatment. The X-ray diffraction (XRD) was used to analyze the structure of silver film deposition. The woven fabric treatments enabled the formation of silver particulate films with particle size larger than the non-woven fabrics. With respect to bacterial growth, all fabrics were shown to be bactericidal for Staphylococcus aureus (S. aureus), while for the Escherichia coli (E. coli), the best results were found for the non-woven fabric (TNT) treated with a flow of 10 cm3/min to both bacteria

Adesão, proliferação e genotoxicidade celular de celulose bacteriana modificada por plasma

Bacterial cellulose (BC) has a wide range of potential applications, namely as temporary substitute skin in the treatment of skin wounds, such as burns, ulcers and grafts. Surface properties determine the functional response of cells, an important factor for the successful development of biomaterials. This work evaluates the influence of bacterial cellulose surface treatment by plasma (BCP) on the cellular behavior and its genotoxicity potential. The modified surface was produced by plasma discharge in N2 and O2 atmosphere, and the roughness produced by ion bombardment characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Cell adhesion, viability and proliferation on BCP were analysed using crystal violet staining and the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium (MTT) method. Genotoxicity was evaluated using the comet and cytokinesis block micronucleus assay. The results show that the plasma treatment changed surface roughness, producing an ideal cell attachment, evidenced by more elongated cell morphology and improved proliferation. The excellent biocompatibility of BCP was confirmed by genotoxicity tests, which showed no significant DNA damage. The BCP has therefore great potential as a new artificial implant

Caracterização de superfícies de titânio modificado por oxidação à plasma

Recent years have seen a significant growth in surface modifications in titanium implants, resulting in shorter healing times in regions with low bone density. Among the different techniques, subtraction by chemical agents to increase oxidation has been applied for surface treatment of dental implants. However, this technique is generally unable to remove undesirable oxides, formed spontaneously during machining of titanium parts, raising costs due to additional decontamination stages. In order to solve this problem, the present study used plasma as an energy source to both remove these oxides and oxidize the titanium surface. In this respect, Ti disks were treated by hollow cathode discharge, using a variable DC power supply and vacuum system. Samples were previously submitted to a cleaning process using an atmosphere of Ar, H2 and a mixture of both, for 20 and 60 min. The most efficient cleaning condition was used for oxidation in a mixture of argon (60%) and oxygen (40%) until reaching a pressure of 2.2 mbar for 60 min at 500°C. Surfaces were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), adhesion and cell proliferation. SEM showed less cell spreading and a larger number of projections orfilopodia in the treated samples compared to the control sample. AFM revealed surface defects in the treated samples, with varied geometry between peaks and valleys. Biological assays showed no significant difference in cell adhesion between treated surfaces and the control. With respect to cell proliferation, the treated surface exhibited improved performance when compared to the control sample. We concluded that the process was efficient in removing primary oxides as well as in oxidizing titanium surfaces

Superfícies de titânio modificadas termoquimicamente por plasma : avaliação da resposta biológica

This laboratory study involves the participation of a group with professionals from different areas that had contributed to the construction of a multidisciplinary knowledge, about biological response of titanium surfaces modified through thermochemical treatment by plasma. Thus, the crystalline phase was previously characterized in relation to the topography, roughness, molhability and nitrogen concentration in the samples surface. It s indispensable that materials implanted can influence in a good cellular response as well as promotes a bacteria action. Surfaces modified by plasma were exposed to different cultures such as: cellular (human osteoblastic) and bacteria (Staphylococcus epidermidis ATCC35984 and Pseudomonas aeruginosa ATCC 27853) in order to evaluate the biological response. It was evaluated the adhesion, proliferation, morphology and cellular preference of human ostheoblastic cells (HOST), as well as the formation of a biofilm and bacteria proliferation. It was still analyzed the bacteria selectivity ability in relation to the surfaces. The software Image Pro Plus was used to the counting of cells and bacteria adhered to the surface of disks. The results were submitted to the variance analysis (ANOVA), and then, by the Kruskal-Wallis test, using GraphPad Instat ® software, version 3.5 to Windows. The nitrided samples in spite of show a higher roughness and molhability showed a smaller bacteria growing and higher cellular proliferation, when compared to non treated samples, indicating that the treated material present a high efficiency to biomedical implants

Modificação superficial do tecido 100% algodão tratado com plasma

The 100% cotton fabric (CO)* treated with plasma of methane CH4 has direct application in all areas that needs of aqueous solutions repellent material like coatings and uniforms applied biomedical, aeronautics, and automobile between others. 100% cotton fabric (CO) samples were treated by plasma with two differents atmosphere: Methane gas (CH4), treatment time was varied in 10 in 10 min. until 60 min., and mixture methane/argon (CH4/Ar), it was varied the proportion 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2 e 9:1, with treatment time of 30 minutes. In both, the fluxe was 5 sccm (second cubic centimeter), pressure 6 mbar, voltage 490 V and current 0,15A. The objective of work was measure the superficial tension of 100% CO then it treated with plasma, using contact angle measures of water and glycerol with the surface. The samples were tested after treatment, with 8 and 12 months to verify the superficial modification effects. It was verified an increase of hydrophobility with the Sessile drop values varied between 116,69º to 137,85º and it carried on after 12 months. The no treated samples shows contact angle equal 0º. OES analysis and Raman spectroscopy were accomplished. In the SEM analysis was verified oligomers. The plasma treatment is correct environmental, It turning greater than conventional treatments

Desenvolvimento de um protótipo para alimentação de pós para aspersão térmica em tocha de plasma

The nanometric powders have special features that usually result in new properties, originating applications or expanding them in various fields of knowledge. Because having a high area/volume ratio, phenomena such as superficial strength of adsorption becomes greater than the weight of the powder which makes more difficult its handling. The high power of agglomeration of these powders requires study and development of equipments to enable its management into the plasma torch. The objective of this work is to develop a powder feeder which can solve the mainly problems about insertion of powder into the thermal spray developed in the laboratory of plasmas, which are carried out with plasma torch arc not transferred (plasma spray). Therefore, it was made a aluminum s powder feeder and tests were performed to verify their operation and determine its rate of deposition by spraying powders of niobium pentoxide (Nb2O5) and titanium dioxide (TiO2) with particle sizes less than 250 mesh (<0.063 mm). We used masses of 0.5 g - 1.0 g and 1.5 g of each powder in tests lasting 15 seconds - 20 to 25 seconds for each mass. The tests were performed in two ways: at atmospheric pressure using argon gas with a flow of 9 l / min as carrier gas and through a Venturi pipe also using argon gas with a flow of 9 l / min as carrier gas and with a flow of 20 l/min as the feed gas passing through the Venturi pipe. The powder feeder developed in this paper is very easy to be handling and building, resulting in feeding rate of 0.25 cm3/min - 1.37 cm3/min. The TiO2 showed higher feeding rates than the Nb2O5 in all tests, and the best rates were obtained with tests using mass 1.5 g and time of 15 seconds, reaching feeding rate of 1.37 cm3/min. The flow of feed had low interference in feeding rate during the tests