Banca de QUALIFICAÇÃO: LARISSE ARAUJO DANTAS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : LARISSE ARAUJO DANTAS
DATA : 03/04/2017
HORA: 14:00
LOCAL: Sala de Reuniões do CB
TÍTULO:

NANOPARTICLES SYNTHESIZED WITH SILVER AND A FRACTION RICH IN ALGINIC ACID AND FUCAN A: PHYSICAL-CHEMICAL CHARACTERIZATION AND EVALUATION OF ITS ANTIPROLIFERATIVE ACTIVITY AGAINST MELANOMA CELLS (B16F10)

PALAVRAS-CHAVES:

Brown Algae, Acid Polysaccharides, Antiproliferative Nanoparticles, Green Synthesis.

PÁGINAS: 92
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Silver nanoparticles (AgNPs) have numerous biological applications, among them the antiproliferative potential. Numerous types of synthesis of silver nanoparticles are referenced in the literature, however, a type of less aggressive and economically viable synthesis, a green symbol, has gained value among the others. In this synthesis process, it is necessary to use a reducing agent and stabilizer which is less toxic to animal cells and to the environment. In this context, biomolecules of marine origin with biological activities described, such as acidic polysaccharides of algae, gain importance. Many acidic polysaccharides (PA) extracted from marine algae are important because they display several activities, such as fucans of the algae Spatoglossum schröederi. These fucans have antioxidant, antiangiogenic and antitumor activity. Due to a few reports of AgNPs synthesis involving algae polysaccharides, it was decided to synthesize AgNPs to the use of a rich fraction in alginic acid and fucan A from S. schröederi algae by a green synthesis process and test the AgNPs against the melanoma lineage B16F10. The PA of the S. schröderi algae were extracted by a process of proteolytic digestion and fractionation with acetone. A higher yield fraction rich in alginic acid and fucan A, the F 0.5v, was employed for a synthesis of AgNPs. The AgNPs were characterized by UV light absorption, chemical composition and mean diameter, polydispersity, and zeta potential by Dynamic Light Scattering (DLS). The formation of the nanoparticles was confirmed by UV-visible spectroscopy in the range of 400-440 nm, they had a diameter of 196 ± 13 nm, polydispersion values below 0.4 and negative zeta potential. The chemical dosages, infrared spectroscopy, and dispersive energy spectroscopy have shown that most AgNPs are composed of acidic polysaccharides. The images obtained by MEV and AFM indicated the spherical format for AgNPs. In addition, It was realized assays like the MTT against 3T3 cell lines (fibroblasts) and B16F10 (murine melanoma) and evaluated the cell death and cell cycle by flow cytometry. Once the AgNPs reached a reduction capacity of the MTT of the 3T3 and B16F10 lineages, having B16F10 the most affected by the AgNPs (0.5 mg / mL) (around 50% of reduction), while silver and F0. 5v did not influence in any of the concentrations. Flow cytometric analysis indicated a high labeling rate with annexin and propidium iodide for the B16F10 cells exposed to AgNPs, in addition to an increase in the percentage of cells in SubG1 in detriment to the other phases. Additional studies are needed to fully elucidate the mechanism of antiproliferative action of AgNPs and to discover other properties of the fraction that are enhanced by the synthesis of nanoparticles. Nevertheless, it can be concluded that it is possible to synthesize AgNPs with S. schröederi acid polysaccharides using a green method and that these AgNPs showed more pronounced antiproliferative activity than their precursors.

MEMBROS DA BANCA:
Presidente - 1549705 - ADRIANA FERREIRA UCHOA
Externo à Instituição - DIEGO DE ARAUJO SABRY - IFRN
Externo à Instituição - LEONARDO THIAGO DUARTE BARRETO NOBRE - UFRN