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1.
Artif Organs ; 42(2): 193-199, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29436026

RESUMO

Bacterial adhesion on three different surfaces: untreated Ti, plasma nitriding, and plasma carbonitriding Ti substrates were investigated. The samples were placed in bacterial cultures of Pseudomonas aeruginosa to assess biofilm formation. The correlation between the amount of bacteria attached to the surface after a lapse of time with nanotopography and physicochemical properties was performed. TiN showed the highest capacity to avoid bacterial adhesion, while presenting intermediate roughness and wettability. Although the surface of TiCN had the highest surface roughness and low contact angle (high wettability), bacterial adhesion was intermediate on this sample. Untreated Ti, even though presenting a smooth surface and low wettability, had the highest tendency to form biofilms.


Assuntos
Ligas/química , Biofilmes/crescimento & desenvolvimento , Nanoestruturas/química , Pseudomonas aeruginosa/fisiologia , Titânio/química , Aderência Bacteriana , Humanos , Infecções por Pseudomonas/prevenção & controle , Propriedades de Superfície , Molhabilidade
2.
Artif Organs ; 40(5): 497-504, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26416762

RESUMO

To evaluate the effect of topography in nanoscale, titanium surfaces were bombarded by argon ions (a chemically inert gas), in an atmosphere of plasma. The effects of surface parameters on morphology, adhesion, proliferation, and MC3T3-E1 preosteoblasts differentiation were analyzed. Nontreated (smooth) surfaces were used as a control. The levels of average roughness (Ra) observed in bombarded and smooth titanium surfaces were of 95 and 14 nm, respectively. The wettability increased on treated surfaces. The number of attached cells (30 and 60 min) was significantly higher on the bombarded surface. The cell proliferation after 3 and 7 days was also significantly higher on the ion-bombarded surface. In addition, the ALP activity and expression of osteocalcin were higher in cells grown on the treated surface. The results showed that bombardment with argon ions increased the roughness and the wettability of the Ti surface, promoting a significant increase in the adhesion, proliferation, and differentiation of preosteoblasts.


Assuntos
Argônio/química , Materiais Biocompatíveis/química , Osteoblastos/citologia , Titânio/química , Animais , Adesão Celular , Diferenciação Celular , Linhagem Celular , Proliferação de Células , Eletrodos , Camundongos , Gases em Plasma/química , Próteses e Implantes , Propriedades de Superfície
3.
Artif Organs ; 37(11): 998-1002, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24251774

RESUMO

The use of polymeric medical devices has stimulated the development of new sterilization methods. The traditional techniques rely on ethylene oxide, but there are many questions concerning the carcinogenic properties of the ethylene oxide residues adsorbed on the materials after processing. Another common technique is the gamma irradiation process, but it is costly, its safe operation requires an isolated site, and it also affects the bulk properties of the polymers. The use of gas plasma is an elegant alternative sterilization technique. The plasma promotes efficient inactivation of the microorganisms, minimizes damage to the materials, and presents very little danger for personnel and the environment. In this study we used plasma for microbial inhibition of chitosan membranes. The membranes were treated with oxygen, methane, or argon plasma for different time periods (15, 30, 45, or 60 min). For inhibition of microbial growth with oxygen plasma, the time needed was 60 min. For the methane plasma, samples were successfully treated after 30, 45, and 60 min. For argon plasma, all treatment periods were effective.


Assuntos
Quitosana , Membranas Artificiais , Gases em Plasma , Esterilização/instrumentação , Quitosana/química , Desenho de Equipamento , Gases em Plasma/química , Esterilização/métodos
4.
Mater Sci Eng C Mater Biol Appl ; 113: 111014, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32487415

RESUMO

We evaluated the effects of titanium plasma nitriding and oxidation on live endothelial cell viscoelasticity. For this, mechanically polished titanium surfaces and two surfaces treated by planar cathode discharge in nitriding (36N2 and 24H2) and oxidant (36O2 and 24H2). Surfaces were characterized regarding wettability, roughness and chemical composition. Rabbit aortic endothelial cells (RAECs) were cultured on the titanium surfaces. Cell morphology, viability and viscoelasticity were evaluated by scanning electron microscopy (SEM), methyl thiazolyl tetrazolium (MTT) assay and atomic force microscopy (AFM), respectively. Grazing Incidence X-ray Diffraction confirmed the presence of TiN0,26 on the surface (grazing angle theta 1°) of the nitrided samples, decreasing with depth. On the oxidized surface had the formation of TiO3 on the material surface (Theta 1°) and in the deeper layers was noted, with a marked presence of Ti (Theta 3°). Both plasma treatments increased surface roughness and they are hydrophilic (angle <90°). However, oxidation led to a more hydrophilic titanium surface (66.59° ± 3.65 vs. 76.88° ± 2.68; p = 0.001) due to titanium oxide films in their stoichiometric varieties (Ti3O, TiO2, Ti6O), especially Ti3O. Despite focal adhesion on the surfaces, viability was different after 24 h, as cell viability on the oxidized surface was higher than on the nitrided surface (9.1 × 103 vs. 4.5 × 103cells; p < 0.05). This can be explained by analyzing the viscoelastic property of the cellular cytoskeleton (nuclear and peripheral) by AFM. Surface oxidation significantly increased RAECs viscoelasticity at cell periphery, in comparison to the nucleus (2.36 ± 0.3 vs. 1.5 ± 0.4; p < 0.05), and to the RAECs periphery in contact with nitrided surfaces (1.36 ± 0.7; p < 0.05) and polished surfaces (1.55 ± 0.6; p < 0.05). Taken together, our results have shown that titanium plasma treatment directly increased cell viscoelasticity via surface oxidation, and this mechanobiological property subsequently increased biocompatibility.


Assuntos
Materiais Biocompatíveis/química , Nitrogênio/química , Oxigênio/química , Gases em Plasma/química , Titânio/química , Animais , Materiais Biocompatíveis/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Citoesqueleto/química , Módulo de Elasticidade , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Oxirredução , Coelhos , Propriedades de Superfície
5.
J Food Prot ; 82(7): 1217-1223, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31233357

RESUMO

HIGHLIGHTS: Discharge of dielectric barriers significantly reduced microbial populations. Treatments resulted in improvement in physical characteristics during storage. Nonthermal plasma provided a 43% (4-day) increase in sample lifetime.


Assuntos
Conservação de Alimentos , Penaeidae , Gases em Plasma , Animais , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Carga Bacteriana , Conservação de Alimentos/métodos , Penaeidae/microbiologia , Gases em Plasma/farmacologia
6.
J Appl Oral Sci ; 23(1): 9-13, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25760262

RESUMO

A current goal of dental implant research is the development of titanium (Ti) surfaces to improve osseointegration. Plasma nitriding treatments generate surfaces that favor osteoblast differentiation, a key event to the process of osteogenesis. Based on this, it is possible to hypothesize that plasma-nitrided Ti implants may positively impact osseointegration. Objective The aim of this study was to evaluate the in vivo bone response to Ti surfaces modified by plasma-nitriding treatments. Material and Methods Surface treatments consisted of 20% N2 and 80% H2, 450°C and 1.5 mbar during 1 h for planar and 3 h for hollow cathode. Untreated surface was used as control. Ten implants of each surface were placed into rabbit tibiae and 6 weeks post-implantation they were harvested for histological and histomorphometric analyses. Results Bone formation was observed in contact with all implants without statistically significant differences among the evaluated surfaces in terms of bone-to-implant contact, bone area between threads, and bone area within the mirror area. Conclusion Our results indicate that plasma nitriding treatments generate Ti implants that induce similar bone response to the untreated ones. Thus, as these treatments improve the physico-chemical properties of Ti without affecting its biocompatibility, they could be combined with modifications that favor bone formation in order to develop new implant surfaces.


Assuntos
Osseointegração/efeitos dos fármacos , Gases em Plasma/uso terapêutico , Tíbia/efeitos dos fármacos , Tíbia/cirurgia , Titânio/uso terapêutico , Animais , Materiais Biocompatíveis , Diferenciação Celular/efeitos dos fármacos , Masculino , Osteoblastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Gases em Plasma/química , Coelhos , Reprodutibilidade dos Testes , Propriedades de Superfície , Fatores de Tempo , Titânio/química , Resultado do Tratamento
7.
J Biomed Mater Res A ; 102(4): 991-8, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23625878

RESUMO

In this study, we evaluated the effect of new plasma-nitrided Ti surfaces on the progression of osteoblast cultures, including cell adhesion, proliferation and differentiation. Ti surfaces were treated using two plasma-nitriding protocols, hollow cathode for 3 h (HC 3 h) and 1 h (HC 1 h) and planar for 1 h. Untreated Ti surfaces were used as control. Cells derived from human alveolar and rat calvarial bones were cultured on Ti surfaces for periods of up to 14 days and the following parameters were evaluated: cell morphology, adhesion, spreading and proliferation, alkaline phosphatase (ALP) activity, extracellular matrix mineralization, and gene expression of key osteoblast markers. Plasma-nitriding treatments resulted in Ti surfaces with distinct physicochemical characteristics. The cell adhesion and ALP activity were higher on plasma-nitrided Ti surfaces compared with untreated one, whereas cell proliferation and extracellular matrix mineralization were not affected by the treatments. In addition, the plasma-nitrided Ti surfaces increased the ALP, reduced the osteocalcin and did not affect the Runx2 gene expression. We have shown that HC 3 h and planar Ti surfaces slightly favored the osteoblast differentiation process, and then these surfaces should be considered for further investigation using preclinical models.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Osteoblastos/citologia , Gases em Plasma/farmacologia , Titânio/farmacologia , Fosfatase Alcalina/genética , Fosfatase Alcalina/metabolismo , Animais , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Células Cultivadas , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Microscopia de Força Atômica , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteocalcina/genética , Osteocalcina/metabolismo , Ratos , Ratos Wistar , Propriedades de Superfície , Difração de Raios X
8.
Int J Oral Maxillofac Implants ; 26(2): 237-44, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21483875

RESUMO

PURPOSE: The aim of this study was to evaluate the characteristics of various titanium surfaces modified by cold plasma nitriding in terms of adhesion and proliferation of rat osteoblastlike cells. MATERIALS AND METHODS: Samples of grade 2 titanium were subjected to three different surface modification processes: polishing, nitriding by plasma direct current, and nitriding by cathodic cage discharge. To evaluate the effect of the surface treatment on the cellular response, the adhesion and proliferation of osteoblastlike cells (MC3T3) were quantified and the results were analyzed by Kruskal-Wallis and Friedman statistical tests. Cellular morphology was observed by scanning electron microscopy. RESULTS: There was more MC3T3 cell attachment on the rougher surfaces produced by cathodic cage discharge compared with polished samples (P < .05). CONCLUSIONS: Plasma nitriding improves titanium surface roughness and wettability, leading to osteoblastlike cell adhesion.


Assuntos
Materiais Revestidos Biocompatíveis/química , Materiais Dentários/química , Compostos de Nitrogênio/química , Osteoblastos/fisiologia , Gases em Plasma/química , Titânio/química , Animais , Compostos Inorgânicos de Carbono/química , Adesão Celular/fisiologia , Contagem de Células , Linhagem Celular , Proliferação de Células , Forma Celular , Polimento Dentário/métodos , Galvanoplastia/métodos , Peróxido de Hidrogênio/química , Microscopia Eletrônica de Varredura , Osteoblastos/ultraestrutura , Oxidantes/química , Ratos , Compostos de Silício/química , Dióxido de Silício/química , Propriedades de Superfície , Molhabilidade
9.
Toxicol Lett ; 189(3): 235-41, 2009 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-19524649

RESUMO

Nanomaterials have unusual properties not found in the bulk materials, which can be exploited in numerous applications such as biosensing, electronics, scaffolds for tissue engineering, diagnostics and drug delivery. However, research in the past few years has turned up a range of potential health hazards, which has given birth to the new discipline of nanotoxicology. Bacterial cellulose (BC) is a promising material for biomedical applications, namely due its biocompatibility. Although BC has been shown not to be cytotoxic or genotoxic, the properties of isolated BC nanofibres (NFs) on cells and tissues has never been analysed. Considering the toxicity associated to other fibre-shaped nanoparticles, it seems crucial to evaluate the toxicity associated to the BC-NFs. In this work, nanofibres were produced from bacterial cellulose by a combination of acid and ultrasonic treatment. The genotoxicity of nanofibres from bacterial cellulose was analysed in vitro, using techniques previously demonstrated to detect the genotoxicity of fibrous nanoparticles. The results from single cell gel electrophoresis (also known as comet assay) and the Salmonella reversion assays showed that NFs are not genotoxicity under the conditions tested. A proliferation assay using fibroblasts and CHO cells reveals a slight reduction in the proliferation rate, although no modification in the cell morphology is observed.


Assuntos
Materiais Biocompatíveis/toxicidade , Proliferação de Células/efeitos dos fármacos , Celulose/toxicidade , Mutagênicos/toxicidade , Células 3T3 , Animais , Células CHO , Celulose/química , Ensaio Cometa , Cricetinae , Cricetulus , Meios de Cultura , Dano ao DNA , Fibroblastos/efeitos dos fármacos , Gluconacetobacter xylinus/química , Camundongos , Microscopia Eletrônica de Transmissão , Nanopartículas/toxicidade , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética
10.
Toxicology ; 262(2): 138-45, 2009 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-19520141

RESUMO

Titanium (Ti) is currently the most widely used material for the manufacture of orthopedic and dental implants. Changes in the surface of commercial pure Ti (cp Ti) can determine the functional response of cells, and is therefore a critical factor for the success of the implant. However, the genotoxicity of titanium surfaces has been poorly studied. Thus, the purpose of this study was to evaluate the genotoxic potential of a new titanium surface developed by plasma treatment using argon-ion bombardment and compare it with an untreated titanium surface. Accordingly, comet assay, analysis of chromosomal aberrations (CAs), and Cytokinesis Block Micronucleus (CBMN) assay were carried out, using CHO-K1 (Chinese hamster ovary) cells grown on both titanium surfaces. Our results show that the untreated titanium surface caused a significant increase in % tail moment, in the number of cells with CAs, tetraploidy, micronucleus frequency, and other nuclear alterations when compared with the negative control and with the plasma-treated titanium surface. This difference may be attributed to increased surface roughness and changes in titanium oxide layer thickness.


Assuntos
Aberrações Cromossômicas/induzido quimicamente , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Mutagênicos/toxicidade , Titânio/toxicidade , Animais , Argônio , Células CHO , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/patologia , Sobrevivência Celular/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/efeitos da radiação , Ensaio Cometa , Cricetinae , Cricetulus , Íons , Testes para Micronúcleos , Mutagênicos/efeitos da radiação , Propriedades de Superfície/efeitos da radiação , Titânio/efeitos da radiação
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