Navegando por Autor "Manfroi, Lucas Augusto"

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    Anatase film on orotracheal tubes to mitigate Staphylococcus aureus
    (American Scientific Publishers) Manfroi, Lucas Augusto; Silva, Michely Glenda Pereira da; Vieira, Angela Aparecida; Macário, Paulo Fabrício; Silva, Newton Soares da; Marques, Francisco Chagas; Vieira, Lucia
    Bacterial contamination in hospital environments is a significant concern for patient admissions. Aiming to reduce contamination, titanium dioxide film (TiO2) in the anatase phase has been prepared on the surface of polyvinyl chloride (PVC) tubes. The PVC tube material was used to study the film’s effectiveness in inhibit- ing bacterial growth and cell viability. The morphology and composition of deposited films were investigated using a Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) map. In addition, Fourier-Transform Infrared Spectroscopy (FTIR) and XRD diffractogram were used to analyze film composition and phase, respectively. The adhesion of TiO2 film on PVC substrate was determined using ScotchTM tape-test according to ASTM: D3359-09, 2010, and the film surface morphology was analyzed by the MEV-FEG tech- nique and EDS map. The bacterial viability was performed with Staphylococcus aureus, and cell viability was performed using L929 strain mouse fibroblasts. The results of TiO2 in the anatase phase deposited by ALD on the PVC surface demonstrate good adherence and the film’s effectiveness in inhibiting bacterial growth and cell viability.
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    Crystalline structure, morphology, and adherence of thick TiO2 films grown on 304 and 316L stainless steels by atomic layer deposition
    (MDPI) Marques, Vagner Eduardo Caetano; Manfroi, Lucas Augusto; Vieira, Angela Aparecida; Pereira, André Luis de Jesús; Marques, Francisco das Chagas; Vieira, Lúcia
    Titanium dioxide (TiO2) thin films are widely used in transparent optoelectronic devices due to their excellent properties, as well as in photocatalysis, cosmetics, and many other biomedical applications. In this work, TiO2 thin films were deposited onto AISI 304 and AISI 316L stainless steel substrates by atomic layer deposition, followed by comparative evaluation of the mixture of anatase and rutile phase by X-ray diffraction, Raman maps, morphology by SEM-FEG-AFM, and adhesion of the films on the two substrates, aiming to evaluate the scratch resistance. Raman spectroscopy mapping and X-ray diffraction with Rietveld refinement showed that the films were composed of anatase and rutile phases, in different percentages. Scratch testing using a diamond tip on the TiO2 film was employed to evaluate the film adherence and to determine the friction coefficient, with the results showing satisfactory adherence of the films on both substrates.
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    Produção e caracterização de filmes finos de TiO2, via técnica de deposição por camada atômica, visando a aplicações biomédicas
    (2021-09-30) Vieira, Lúcia; Silva, Newton Soares da; Ramirez Ramos, Marco Antonio; Marques, Francisco das Chagas; Sales, Rita de Cássia Mendonça; Manfroi, Lucas Augusto; São José dos Campos
    Com a existência recorrente de bactérias mais resistentes dentro de ambientes hospitalares, associada à imunidade reduzida dos pacientes que os torna mais propensos as infecções. Este trabalho teve como objetivo desenvolver a deposição de filmes finos de dióxido de titânio (TiO2) por meio da técnica de deposição por camada atômica (ALD) sobre a superfície de materiais amplamente utilizados em ambiente hospitalar, como o alumínio, o policloreto de vinila (PVC) e o poliuretano (PU). Para determinar a estrutura química do filme foram utilizadas as análises de Espectroscopia no Infravermelho por Transformada de Fourier (FTIR), com espectroscopia Raman e Espectroscopia por Energia Dispersiva (EDS), que indicaram a distribuição uniforme do filme de TiO2 na fase anatase. Para analisar a morfologia foram utilizadas a Microscopia Eletrônica de Varredura (MEV), a Microscopia de Força Atômica (AFM) e a perfilometria, que apresentaram uma morfologia granular e em placas. A espessura do filme foi determinada por perfilometria de contato utilizando um degrau entre o filme e o substrato e a fotomicrografia de um corte perpendicular ao filme. A aderência foi determinada pelo teste de fita e analisada pela técnica MEV-FEG e mapa de EDS, demonstrando uma boa aderência do filme. Para determinar a atividade biológica foram utilizados testes de viabilidade bacteriana e viabilidade celular, que demonstrou a eficiência do filme como bactericida sem apresentar toxicidade as células. Com base nos resultados obtidos o filme de TiO2 se mostrou muito promissor em ser utilizado para revestir dispositivos médicos e superfícies hospitalares como forma de reduzir a contaminação.
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    Tribocorrosion Susceptibility and Osseointegration Studies of Silicon–Carbon–Titanium Oxide Coatings Produced on SS316L by Laser Cladding
    (Springer Nature Link) Vieira, Angela Aparecida; Manfroi, Lucas Augusto; Lobo, Larissa Zamboni; Santos, Thaisa Baesso; Silva, Silvelene Alessandra da; Vasconcelos, Getúlio; Radi, Polyana Alves; Silva, Newton Soares da; Vieira, Lucia
    Metallic implants are frequently exposed simultaneously to cyclic micromovements and a corrosive medium at the interface between implant and bone, constituting a tribocorrosive environment. Ions from natural body fluids can increase the release of debris in the wear zone. This debris can penetrate soft or hard tissue, leading to implant failure and metallic contamination of the tissues around the prosthesis. Surface modification of implants has been studied to improve the lifespan of metallic implants in the body. In this work, a CO2 laser was used to irradiate silicon carbide with and without anatase titanium oxide (TiO2), in order to produce protective coatings for improving the tribocorrosion and osseointegration performance of stainless steel (SS316L). Tribocorrosion resistance and osseointegration tests were performed using simulated body fluid (SBF), in order to understand the behavior in this environment. Chemical composition and hardness analyses showed that the coatings were effective in improving passivation of the surface, when compared to bare SS316L. Osteoblasts were well dispersed on these surfaces, displaying improved proliferation and viability, compared to the SS316L sample. A statistically significant increase of cell viability was observed when the surface was covered with a low silicon content coating.