Banca de DEFESA: HELOIZA FERNANDA OLIVEIRA DA SILVA ATHAYDE

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : HELOIZA FERNANDA OLIVEIRA DA SILVA ATHAYDE
DATA : 25/10/2019
HORA: 09:00
LOCAL: Auditório do CCET
TÍTULO:

GOLD AND SILVER NANOPARTICLES APPLIED TO BIOLOGICAL SYSTEMS

PALAVRAS-CHAVES:

Gold nanoparticles, HT-29, silver nanoparticles, Escherichia coli.

PÁGINAS: 162
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Físico-Química
ESPECIALIDADE: Química do Estado Condensado
RESUMO:

Neoplasia and bacterial resistance are among the main challenges in the biomedical área. It requires study and development of alternative. Metal nanoparticles have shown promise in such applications. This thesis presents applications of gold and silver nanoparticles (NanoAu and NanoAg, respectively) to biological systems. NanoAu are considered as potential drug delivery platforms. However, understanding the interaction of these particles with living organisms before their use as nanocarriers is essential. Thus, the first study presents the synthesis and characterization of NanoAu and the investigation of anti-inflammatory, analgesic and antitumor effects, as well as their biodistribution and their effect on various tissue types. The NanoAu were synthesized by enviromental friendly route and characterized by transmission electron microscopy (TEM) and UV-Vis spectroscopy (UV-vis). Subsequently, HT-29 cells were exposed to NanoAu and apoptosis was evaluated by caspase-3 activity. Regarding in vivo assays, NanoAu were administered to female Swiss mice and male rats for further evaluation of their anti-inflammatory and analgesic properties. NanoAu biodistribution and its impact on tissues were studied by UV-Vis spectroscopy and histopathological analysis, respectively. Cell apoptosis was dose dependent for NanoAu concentrations between 40 µg ml -1 and 80 µg ml -1 (p <0.05). The best anti-inflammatory activity was observed at 1500 mg kg-1, which led to a reduction of 49.3% in leukocyte migration. NanoAu showed peripheral analgesia at 1500 mg kg-1 and were found in the liver, spleen, kidney and lung of Swiss mice. Histopathological examination revealed extravasation of red blood cells in the lung. The second study addresses the investigation of the metabolic synergistic effect of NanoAg combined with doxycycline hiclate, DO. ATR-FTIR biospectroscopy of bacterial samples of Staphylococcus aureus was used. PCA was applied to the spectrum group showing a pattern of differentiation between the classes. Due to the complexity of the obtained data (presenting overlapping bands and enough variance within the same class), it was necessary to use the PLS-DA variable selection tool. It was identified that all antimicrobials in this study interfere with protein synthesis. Sensitivity values of 75%, 100% and 75% for Control, NanoAg and DO respectively. It was also determined whether or not there was a statistical difference in the mean absorbance values, which allowed us to indicate in which cases the biomarkers were more expressed, which suggested the possible cause of the synergy of the antibacterial effect of NanoAu combined with doxycycline hyclate. The results obtained in both studies confirm the potential of synthesized nanoparticles in our research group as possible nanocarriers.

MEMBROS DA BANCA:
Presidente - 1958858 - LUIZ HENRIQUE DA SILVA GASPAROTTO
Externo ao Programa - 1639820 - ARNOBIO ANTONIO DA SILVA JUNIOR
Externo ao Programa - 1883170 - MAURICIO ROBERTO BOMIO DELMONTE
Externo à Instituição - PIERRE BASÍLIO ALMEIDA FECHINE - UFC
Externo à Instituição - SHERLAN GUIMARÃES LEMOS - UFPB