Navegando por Autor "Lobo, Larissa Zamboni"

Agora exibindo 1 - 2 de 2
  • Imagem de Miniatura
    Item
    Sputtering of micro-carbon-silver film (μC-Ag) for endotracheal tubes to mitigate respiratory infections
    (IOP science) Silva, Michely Glenda Pereira da; Manfroi, Lucas Augusto; Lobo, Larissa Zamboni; Vieira, Angela Aparecida; Macário, Paulo Fabrício; Fukumasu, Newton Kiyoshi; Silva, Newton Soares da; Tschiptschin, André Paulo; Marques, Francisco das Chagas; Vieira, Lucia
    Polyurethane (PU) substrates are biocompatible materials widely used to manufacture endotracheal tubes. However, in common with other biomedical materials, they are liable to the formation of microbial films. The occurrence of pneumonia in intubated patients treated at intensive care units often takes the form of ventilator-associated pneumonia (VAP). The issue relates to the translocation of pathogenic microorganisms that colonize the oropharyngeal mucosa, dental plaque, stomach, and sinuses. New protective materials can provide a more effective therapeutic approach to mitigating bacterial films. This work concerns microcrystalline carbon film containing dispersed silver nanoparticles (μC-Ag) deposited on PU substrates using a physical vapor deposition sputtering process. For the first time, carbon paper was used to produce a carbon target with holes exposing a silver disk positioned under the carbon paper, forming a single target for use in the sputtering system. The silver nanoparticles were well distributed in the carbon film. The adherence characteristics of the μC-Ag film were evaluated using a tape test technique, and electron dispersive x-ray mapping was performed to analyze the residual particles after the tape test. The microbicidal effect of the thin film was also investigated using species S. aureus, a pathogenic microorganism responsible for most infections of the lower respiratory tract involving VAP and ventilator-associated tracheobronchitis (VAT). The results demonstrated that μC-Ag films on PU substrates are promising materials for mitigating pathogenic microorganisms on endotracheal tubes.
  • Imagem de Miniatura
    Item
    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.