Navegando por Palavras-chave "nanopartículas"
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- ItemSomente MetadadadosEstudo da integração da tela de polipropileno recoberta com materiais nanoestruturados em ratos(Universidade Federal de São Paulo (UNIFESP), 2014-05-28) Tussi Júnior, Roberto [UNIFESP]; Koh, Ivan Hong Jun Koh [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Purpose: Evaluate the biocompatibility of polypropylene mesh coated with nanostructured materials and analysis of abdominal content adhesions with polypropylene mesh. Methods: After deposition of silver, carbon and carbon plus silver nanoparticles, using the Nonthermal plasma technique at Plasma and Processes Laboratory of ITA. The meshes were implanted at acute defects of the anterior abdominal wall of female rats Wistar- EPM. The histology was used to analysis of mesh tissue interaction using HE and Picrosirius Red. The study of adhesions was done through sheer numbers of adhesions to the prosthesis, Zühlke criteria for adhesion strength and Diamond criteria for percentage of area covered by adhesions. Results: The polypropylene mesh coated with carbon and silver exclusively demonstrated an excellent biocompatibility with the absence of acute or chronic inflammatory response and with reduced type I collagen and increase type III collagen. However meshes treated with carbon and silver in the sequence presented with harmful perpetuation of acute inflammatory activity. In this group the fibroblasts collagen production was absent. Evidencing a higher degree of antigenicity than control group. The analysis of the number of adhesions was not statistically significant between groups, as well as the strength of the same Zühlke criteria. Already the percentage of area attached to the prosthetic tissue showed statistical significance in the groups covered with silver carbon and unique compared to the polypropylene group. Conclusion: The deposition of nanocomposites of silver and carbon on the polypropylene mesh showed a reduction of antigenicity with improved tissue incorporation. The percentage of mesh surgical adhesions were also benefited this group. Nanotechnological meshes treatment did not prevent the formation of adhesions. Different Nonthermal methods deposition and combinations of nanoparticles may influence with the biological response.
- ItemSomente MetadadadosMagnetofecção mediada por nanopartículas de óxido de ferro em tumores de glioblastoma para posterior aplicação terapêutica da magneto hipertermia: estudos in vitro e in vivo(Universidade Federal de São Paulo (UNIFESP), 2015-12-18) Aguiar, Marina Fontes de Paula [UNIFESP]; Contreras, Lionel Fernel Gamarra Contreras [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Objective: Elucidate the in vitro and in vivo magnetofection process in glioblastoma tumors induced by C6 cells, with future perspective for therapeutic application of magneto hyperthermia. Therefore, superparamagnetic iron oxide nanoparticles conjugated with fluorescent Rhodamine-B molecules were used along with an external magnetic field for active tumor targeting. Methods: For magnetofection process, a resistive electromagnet capable of generating a variable magnetic field and pole geometry able to create a magnetic field gradient, was built. Previous in vitro tests with 50 nm hydrodynamic size NOFRhod were made to verify the transport and specific local accumulation. For in vivo targeting, the magnetic field of the poles was adjusted to 0 T (control) or 1,3 T (experimental value) and the nanoparticles were administrated by three different routes: tumor local, tail vein or carotid artery. Results: At first, we demonstrated that nanoparticles in this study are stable in DMEM culture medium and when dispersed in saline or PBS at a concentration of 50 µgFe/mL. The cell labeling analysis by prussian blue and fluorescent microscopy showed that NOF-Rhod are efficient for this purpose in all used concentrations (1, 10, 30 e 50 ug/mL), being enhanced by external magnetic field application. Besides that, cytotoxicity assay showed that cell death caused by these nanoparticles was barely evident. The volumetry study by MRI and histology demonstrated that in all used concentrations the tumor growth was evident and proportional both according to the day and the C6 cell concentration (104 , 105 ou 106 ). The in vitro tests showed that nanoparticle aggregation was efficient in all magnetic field gradients used. Moreover, the oblique steel pole addition created a punctual nanoparticle accumulation in one hose?s side, being this artifice selected for subsequent in vivo studies. The MRI monitoring was effective for NOF-Rhod identification in tumor region after local administration, showed an important signal reduction. The MRI sensibility, moreover, was not able to detect NOF-Rhod in tumor region after tail vein or carotid administration, further studies for these administration parameters are required. The in vivo magnetofection process analysis by histology, however, demonstrated more sensibility than MRI, evidencing iron concentration in tumor after the three NOFRhod administration routes. Furthermore, targeting intravenous administration with an external magnetic field was capable to increasing nanoparticle accumulation in tumor region. Conclusion: Taken together, our in vitro and in vivo results showed the NOF-Rhod magnetic targeting efficience, being this strategy a promisse tool for further applications of magneto hyperthermia technique.
- ItemAcesso aberto (Open Access)Membranas de celulose não-modificada contendo nanopartículas de paládio preparadas em meio de líquido iônico: preparação, caracterização e aplicação(Universidade Federal de São Paulo, 2023-10-17) Carneiro, Nicollas Azevedo [UNIFESP]; Camilo, Fernanda Ferraz [UNIFESP]; http://lattes.cnpq.br/6334598937296642; https://lattes.cnpq.br/6349799118208610Neste trabalho, apresentamos um método inovador para a síntese de nanopartículas de paládio (PdNPs) usando o líquido iônico cloreto de 1-butil-3-metilimidazólio (BMImCl) como solvente, agente estabilizante e molde. As nanopartículas de Pd (PdNPs) foram obtidas a partir da redução química de soluções de PdCl2 em BMImCl em três diferentes concentrações: 10, 50 e 100 mM. O tetraidroborato de tetrabutilamônio (TBABH4), solubilizado no mesmo líquido iônico, foi introduzido como agente redutor para os íons Pd2+. A conversão para PdNPs foi evidenciada por análise espectroscópica e confirmada por microscopia eletrônica de transmissão, que revelou partículas esféricas com diâmetros menores que 5 nm, um tamanho considerado pequeno, o que pode contribuir para uma maior eficiência catalítica. Subsequentemente, combinamos celulose solubilizada em BMImCl com as PdNPs, regenerando-as em membranas. Essas membranas contêm teores de paládio variando de 0,03 a 8,0 % em massa e apresentam alta estabilidade térmica. Além disso, são insolúveis em ambientes aquosos e foram eficazmente empregadas como catalisadores heterogêneos em reações de acoplamento C-C Suzuki-Miyaura sem o uso de ligantes. A incorporação de PdNPs em membranas de celulose traz benefícios como redução de custos, facilitação nos processos de isolamento e potencial reutilização, comparativamente aos catalisadores tradicionais à base de Pd.