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Doctoral Thesis
DOI
https://doi.org/10.11606/T.97.2022.tde-07122022-105243
Document
Author
Full name
Cláudia Santos Salim
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Lorena, 2022
Supervisor
Committee
Florenzano, Fábio Herbst (President)
Sampaio, Simone de Fátima Medeiros
Saron, Clodoaldo
Tada, Dayane Batista
Title in Portuguese
Síntese de copolímeros em bloco para a prospecção da formação de sistemas vesiculares (polimerossomos)
Keywords in Portuguese
Copolímeros
Polimerossomos
RAFT
Abstract in Portuguese
Copolímeros anfifílicos podem formar sistemas vesiculares em meio aquoso, chamados hoje de polimerossomos. Os polimerossomos podem responder a estímulos externos e ter diversas aplicações: na compartimentalização de produtos, reagentes e/ou catalizadores, aumentando a eficiência e a seletividade dos processos (como nanorreatores); encapsulamento de materiais tóxicos, proteínas e enzimas; no carreamento de fármacos; montagem de organelas artificiais, entre muitas outras. O objetivo desse trabalho foi sintetizar copolímeros anfifílicos com diferentes composições (combinadas entre os monômeros DMAEMA, MAA, MMA, HEMA, STY e tBA) e massas molares médias, visando a obtenção de diblocos para montagem de polimerossomos, os quais foram estudados quanto à incorporação e isolamento de moléculas hidrofílicas. As sínteses foram via Transferência Reversível de Cadeia por Adição-Fragmentação devido às especificidades da técnica, em duas etapas, sendo a primeira gerou o macroagente para a segunda. Os polímeros foram caracterizados por Ressonância Magnética Nuclear de prótons, Espectroscopia de infravermelho com Transformadas de Fourier e Cromatografia de Permeação em Gel. As vesículas poliméricas foram formadas pelo método de Troca de solventes, caracterizadas por Espalhamento de Luz Dinâmico e, em alguns casos, por microscopias. Por fim, os polimerossomos foram testados quanto à capacidade de isolarem moléculas hidrofílicas e liberarem o conteúdo quando desejado por Espectrofotometria UV-Vis e medidas da atividade enzimática pelo método de Miller. Após análise da cinética de reação por Espectrofotometria, concluiu-se que as vesículas de PDMAEMA277-b-OS86 foram capazes de isolar moléculas de azul de metileno de um agente redutor. Os polimerossomos de P(DMAEMA65-co-HEMA3)-b-PS327 foram analisados por Microscopia Eletrônica de Transmissão, a qual demonstrou a formação de coloides com o diâmetro de centenas de nanômetros (compatível com vesículas) e a forma esferoidal. Por fim, o PS98-b-PAA343 encapsulou a enzima invertase, sua a membrana foi rompida usando o tensoativo Triton X-100 e o conteúdo foi liberado e a diferença entre esses materiais pôde ser observada com o aumento da atividade enzimática.
Title in English
Synthesis of block copolymers for prospecting the formation of vesicular systems (polymersomes)
Keywords in English
Copolymers
Polymersomes
RAFT
Abstract in English
Amphiphilic copolymers can form vesicular systems in aqueous media, today called polymerosomes. Polymerosomes can respond to external stimuli and several applications: compartmentalization of products, reagents and/or catalysts, increasing the efficiency and selectivity of processes (such as nanoreactors); encapsulation of toxic materials, proteins and enzymes; in drug delivery; assembly of artificial organelles, among many others. The objective of this work was to synthesize amphiphilic copolymers with different compositions (combined between the monomers DMAEMA, MAA, MMA, HEMA, STY and tBA) and average molar masses, aiming at obtaining diblocks for the assembly of polymerosomes, which were studied for their incorporation and isolation of hydrophilic molecules. The syntheses were performed by Reversible AdditionFragmentation Chain Transfer due to the specificities of the technique, in two stages, the first being generated the macroagent for the second. The polymers were characterized by Proton Nuclear Magnetic Resonance, Fourier Transform Infrared Spectroscopy and Gel Permeation Chromatography. The polymeric vesicles were formed by the Solvent Switch method, characterized by Dynamic Light Scattering and, in some cases, by microscopy. Finally, the polymerosomes were tested for their ability to isolate hydrophilic molecules and release the content when desired by UVVis Spectrophotometry and measurements of enzymatic activity by Miller's method. After analyzing the reaction kinetics by spectrophotometry, it was concluded that PDMAEMA277-b-PS86 vesicles were able to isolate methylene blue molecules from a reducing agent. P(DMAEMA65-co-HEMA3)-b-PS327 polymerosomes were analyzed by Transmission Electron Microscopy, which demonstrated the formation of aggregates with a diameter of hundreds of nanometers (compatible with vesicles) and a spheroidal shape. Finally, PS98-b-PAA343 encapsulated the invertase enzyme, its membrane was broken using Triton X-100 surfactant and the content was released and the difference between these materials could be observed with the increase in enzymatic activity.
 
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EMT22005_C.pdf (3.19 Mbytes)
Publishing Date
2022-12-07
 
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