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Previous issue date: 2017-04-17 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Nanopart?culas de prata (AgNPs) possuem diversas aplica??es biom?dicas, dentre elas destaca-se o potencial antiproliferativo. In?meros tipos de s?ntese de nanopart?culas de prata encontram-se descritos na literatura, no entanto, um tipo de s?ntese menos agressiva e mais economicamente vi?vel, a s?ntese verde, tem ganhado import?ncia dentre as demais. Neste processo de s?ntese ? necess?rio o uso de um agente redutor e estabilizante que n?o sejam t?xicos para as c?lulas animais e para o meio ambiente. Nesse contexto, a associa??o de biomol?culas de origem marinha com atividades biol?gicas j? descritas, como os polissacar?deos ?cidos de algas, ?s AgNPs ganham import?ncia. Muitos polissacar?deos ?cidos (PA) extra?dos de algas marinhas destacam-se por exibir diversas atividades, como exemplo as fucanas da alga Spatoglossum schr?ederi. Estas fucanas apresentam atividade antioxidante, antiangiog?nica, antitumoral, dentre outras. Devido aos poucos relatos de s?ntese de AgNPs envolvendo polissacar?deos de algas, este trabalho teve por objetivo sintetizar AgNPs com uma fra??o rica em ?cido alg?nico e fucana A da alga S. schr?ederi por um processo de s?ntese verde, e testar as AgNPs obtidas frente ? linhagem de melanoma B16F10. Os PA da alga S. schr?ederi foram extra?dos por um processo de digest?o proteol?tica e fracionados com acetona. A fra??o de maior rendimento e rica em ?cido alg?nico e fucana A, a F0.5 v, foi empregada para a s?ntese das AgNPs. A caracteriza??o das AgNPs obtidas contemplou a an?lise de absor??o de luz UV, composi??o qu?mica, di?metro m?dio, polidispers?o, potencial zeta, espectroscopia de infravermelho (FTIR) e a espectroscopia de energia dispersiva (EDS), microscopia eletr?nica de varredura (MEV) e microscopia de for?a at?mica (MFA). As an?lises por espectroscopia de UV-vis?vel na faixa entre 400 e 440 nm confirmaram a forma??o das AgNPs, estas apresentaram di?metro de 196 ? 13 nm, valores de polidispers?o abaixo de 0,4 e potencial zeta negativo. As dosagens qu?micas, o FTIR e o EDS revelaram que a maior parte das AgNPs ? composta por polissacar?deos ?cidos. As imagens obtidas por MEV e MFA indicaram um formato esf?rico para as AgNPs. A atividade antiproliferativa foi avaliada pelo m?todo do MTT frente ?s linhagens celulares B16F10 e fibroblastos 3T3, e por citometria de fluxo foi investigado sua a??o na morte e no ciclo celular. As AgNPs afetaram a capacidade de redu??o do MTT das linhagens 3T3 e B16F10, sendo esta mais evidenciada para a B16F10, pois as AgNPs (0,5 mg/mL) conseguiram reduz?-la em torno de 50%, enquanto a prata i?nica e a F0.5 v em nenhuma das concentra??es influenciaram na redu??o do MTT. As an?lises por citometria de fluxo apontaram uma elevada taxa de marca??o para anexina V e iodeto de prop?dio para as c?lulas B16F10 expostas ?s AgNPs, al?m de um aumento na porcentagem das c?lulas em Sub-G1 em detrimento ?s outras fases. Estudos adicionais s?o necess?rios para elucidar completamente o mecanismo de a??o antiproliferativo das AgNPs e descobrir outras propriedades da fra??o que s?o intensificadas pela s?ntese de nanopart?culas. Entretanto, pode-se concluir que ? poss?vel sintetizar AgNPs com polissacar?deos ?cidos de S. schr?ederi usando um m?todo verde e que essas AgNPs apresentaram atividade antiproliferativa mais pronunciada que seus percussores. / Silver nanoparticles (AgNPs) have several biomedical applications, among them the antiproliferative potential. Numerous types of synthesis of silver nanoparticles are found in the literature, however, a type of synthesis less aggressive and more economically viable, a green synthesisl, has gained value among the others. In this synthesis process, it is necessary to use a reducing agent and stabilizer which are non-toxic to animal cells and to the environment. In this context, an association of biomolecules of marine origin with biological activities already described, such as the polysaccharide acids of algae, to the AgNPs gain importance. Many acidic polysaccharides (PA) extracted from marine algae are distinguished by their different activities, such as the algae Spatoglossum schr?ederi. These fucans have antioxidant, antiangiogenic, antitumor activity, among others. Due to the few reports of AgNPs synthesis involving algae polysaccharides, the objective of this work was to synthesize AgNPs with a rich fraction of alginic acid and fucan A from the S. schr?ederi algae by a green synthesis process and to test the AgNPs obtained on the lineage of melanoma B16F10. The PA of the S. schr?ederi algae was extracted by a proteolytic digestion process and fractionated with acetone. The higher yield fraction rich in alginic acid and fucan A, F0.5 v, was used for synthesis of the AgNPs. The characterization of the AgNPs obtained contemplated an analysis of UV light absorption, chemical composition, average diameter, polydispersity, zeta potential, infrared spectroscopy (FTIR), dispersive energy spectroscopy (EDS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The analyzes by UV-visible spectroscopy in the range between 400 and 440 nm confirmed the formation of AgNPs, they presented 196 ? 13 nm diameter, polydispersion values below 0.4 and negative zeta potential. The chemical dosages, FTIR and EDS revealed that most AgNPs are composed of acidic polysaccharides. The images obtained by SEM and AFM indicated a spherical format for AgNPs. The antiproliferative activity was evaluated by the MTT method against B16F10 cell lines and 3T3 fibroblasts, and by flow cytometry, its action on death and cell cycle was investigated. The AgNPs affected the ability to reduce MTT from the 3T3 and B16F10 lineages, but these were evidenced for a B16F10, the AgNPs (0.5 mg/mL) were able to reduce by around 50%, while a silver ion and F0.5 v at any of the concentrations influenced the reduction of MTT. Flow cytometry analyzes indicated a high labeling rate for annexin V 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. However, it can be concluded that it is possible to synthesize AgNPs with acidic polysaccharides from S. schr?ederi using a green method and that these AgNPs showed more pronounced antiproliferative activity than their precursors.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/23436 |
| Date | 17 April 2017 |
| Creators | Dantas, Larisse Ara?jo |
| Contributors | 04647720446, http://lattes.cnpq.br/4991977240761750, Scortecci, Katia Castanho, 13451112825, http://lattes.cnpq.br/4808910380593455, Santos, Pablo de Castro, 01002547482, http://lattes.cnpq.br/6456286305129050, Rocha, Hugo Alexandre de Oliveira, Costa, Leandro Silva |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM BIOQU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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