Banca de DEFESA: Aline Beatriz da Silva Santos

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : Aline Beatriz da Silva Santos
DATE: 30/08/2023
TIME: 15:00
LOCAL: Auditório 2
TITLE:

Development of Gold/Pluronic Nanocomposites for Biological Applications

KEY WORDS:

gold nanoparticle (AuNP-PLU), Pluronic® F-127, nanocomposite, localized surface plasmon resonance band (LSPR), aluminum phthalocyanine chloride (AlClPc), reactive oxygen species (ROS), photodynamic therapy (PDT), computed tomography (CT), pregnant rats, evaluation of maternal fetal toxicity.

PAGES: 92
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

The objective of this work is the preparation, characterization and biomedical application of nanocomposites formed by gold nanoparticles and Pluronic® F-127. The nanocomposites were synthesized from the mixture of Pluronic® triblock copolymer solutions varying the concentrations in (0.5; 2.0 mmol.L-1), and chloroauric acid (HAuCl4) (0.1; 2. 0, 3.0, 4.0 mmol.L-1), in a UV radiation chamber (254nm), at room temperature. In this reaction, the copolymer acts in the reduction of gold ions and stabilization of gold nanoparticles, forming the AuNP-PLU colloidal nanocomposite. The ultraviolet-visible spectroscopy analysis shows that the surface plasmonic resonance band of the nanocomposites is located between 525 to 529 nm. The micrographs of the nanocomposites obtained show gold nanoparticles with a spherical, triangular or cylindrical shape, with an average diameter of 5 to 44 nm. The average hydrodynamic (DH) size obtained by dynamic light scattering ranged from 31 to 68 nm. For the biological application experiments, nanocomposites 2.0AuNP-PLU:2.0 and 2.0AuNP-PLU:0.5 were chosen, as they presented greater reproducibility and stability of the physical-chemical characteristics after synthesis. These nanocomposites were used in the photochemical test with 1,3-diphenylisobenzofuran (DPBF), in which the formation of reactive oxygen species (ROS) was observed. To carry out this test, the nanoparticles were associated with a photosensitizer, aluminum phthalocyanine chloride (AlClPc), in concentrations of 0.1 to 5.0 µg. After mixing with the photosensitizer, the nanocomposites were characterized by ultraviolet-visible spectroscopy, in which it was possible to observe a new peak at 680 nm coming from the photosensitizer. The new average hydrodynamic (DH) size of the nanocomposites with the photosensitizer was from 31 to 73 nm. The characterization was performed by Raman spectroscopy and by infrared spectroscopy (FTIR-ATR), in which changes were observed in the spectra of the nanocomposites due to the bonds between the ether groups of the pluronic with the nitrogenous groups of the aluminum phthalocyanine chloride. In another approach, the 2.0AuNP-PLU:2.0 nanocomposite was used to study the maternal and fetal toxicological effects of its administration during pregnancy in rats and fetuses. The results showed that the nanocomposite is safe for both the mother and the fetus at a dose of 137.5 μg/kg. Therefore, the administration of the nanocomposite did not result in changes in fetal development, nor changes greater than 5% in the observed organs. The same 2.0AuNP-PLU:2.0 nanocomposite was investigated as a contrast agent in computed tomography. The results showed that the contrast agent is comparable to the commercially used contrast (Optiray® 320) for the same beam energy.

COMMITTEE MEMBERS:
Externa ao Programa - 1122773 - ELAINE ROSE MAIA - UnBExterna à Instituição - LUANA ALVES DE FREITAS AFIUNE - DELTA
Presidente - 1122819 - MARIA APARECIDA GODOY SOLER PAJANIAN
Externo ao Programa - 1764408 - PAULO EDUARDO NARCIZO DE SOUZA - UnB