Detalhes bibliográficos
| Ano de defesa: |
2019 |
| Autor(a) principal: |
Lopes, Leonardo Quintana Soares |
| Orientador(a): |
Santos , Roberto Christ Vianna |
| Banca de defesa: |
Alves, Sydney Hartz,
Peres, Paulo Eldevar Corrêa,
Rech, Virgínia Cielo,
Becker, Ana Paula |
| Tipo de documento: |
Tese
|
| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Universidade Franciscana
|
| Programa de Pós-Graduação: |
Programa de Pós-Graduação em Nanociências
|
| Departamento: |
Biociências e Nanomateriais
|
| País: |
Brasil
|
| Palavras-chave em Português: |
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| Palavras-chave em Inglês: |
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| Área do conhecimento CNPq: |
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| Link de acesso: |
http://www.tede.universidadefranciscana.edu.br:8080/handle/UFN-BDTD/798
|
Resumo: |
Biofilms are microbial clusters surrounded by a matrix of extracellular polysaccharides. In the 21st century it has been proven that the ability of microorganisms to form biofilm significantly increased drug resistance, making treatment difficult. In these cases, the therapeutic options are the removal of the infected tissue or implant or to combine and even increase the dose of drug administered. In both cases, there may be negative consequences related to increased hospitalization time and costs, as well as renal overload caused by high doses of drugs and increased morbidity and mortality. Therefore, the search for new strategies and technologies to combat these infections has been an important target in the research. Glycerol monolaurate is used in the pharmaceutical and food industry as an emulsifying agent. It presents antimicrobial action, however, its low solubility in water makes difficult its use as a therapeutic alternative due to low biodistribution. In this context, nanotechnology has shown promising results increasing the solubility and bioavailability of the agent and thus reaching the most difficult sites of infection as in the case of biofilms. Thus, the objective of this work was to use nanocapsules containing glycerol monolaurate for the treatment of biofilms of bacteria and yeasts, as well as to verify aspects of toxicity related to this therapy. Nanocapsules produced by the interfacial deposition method of the preformed polymer were used. The nanoparticles were characterized in terms of the mean diameter, polydispersity index, zeta potential, pH and transmission electron microscopy morphology, which showed acceptable values to predict system stability. Pseudomonas aeruginosa strains PAO1 and Candida albicans (ATCC 14053) were used for the microbiological tests. Initially the minimum inhibitory and bactericidal / fungicidal concentration determination was made. Biofilm quantification, growth curve, and fluorescence and atomic force microscopy tests were performed. For toxicity tests, cell lines were used as VERO cells, peripheral blood mononuclear cells, and erythrocytes. A viability test, lactate dehydrogenase enzyme test, thiobarbituric acid reactive substance test (TBARS), the percentage of hemolysis and comet assay was performed. In addition to the in vitro assays, an in vivo toxicity test with Rhamdia quelen fish was performed. Initial tests showed that the nanoparticles were able to inhibit microbial growth in a lower concentration when compared to the free glycerol monolaurate. The antibiofilm assays showed approximately 50% reduction of the biofilm treated with the nanoparticles containing glycerol monolaurate. In addition, treatment with the nanoparticles almost completely eliminated the biofilm in 48 hours while the monolaurate in the free form had no effect. The viability assays demonstrated that the free glycerol monolaurate has an important cytotoxic effect, while the nanocapsules showed a protective effect. Nanostructured monolaurate demonstrated a reduction in cell damage in assays such as lactate dehydrogenase release, TBARS detection, and hemolysis percentage. The in vivo assay performed with fish showed high mortality caused by the substance in the free form while the nanocapsules demonstrated a significant reduction in the mortality of the animals. |
