Made available in DSpace on 2017-07-10T15:14:33Z (GMT). No. of bitstreams: 1 DissertacaoPauloCremonez.pdf: 2171148 bytes, checksum: 995ec964a2e225fff5ce8c4199d9738e (MD5) Previous issue date: 2015-02-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The increase in the generation and accumulation of solid residues mainly compounds for packaging, led to a search for development technologies of plastics and biodegradable films eligible for treatment by conventional processes used for organic materials. Currently, various plastics, expanded polystyrene and biodegradable films are produced from the most diverse forms. The present work aims to evaluate primarily anaerobic degradation of biodegradable polymers based on manioc starch. The dissertation is divided into two chapters, the first aims at assessing the anaerobic digestion of organic polymer based on manioc starch diluted in residual water of pigs in various concentrations. Meanwhile, the second chapter aims to compare the cassava-based biodegradable polymer with other material widely studied as an additive in the biodigestion process, the glycerol. The anaerobic biodigestion process proves to be effective in the degradation and stabilization of polymeric materials based on cassava and guarantee high rates of production of biogas, rich in methane that can be used for multiple purposes, ensuring energy savings in production processes. The polymer can still be considered interesting additive on digestion processes of other agro-industrial waste aimed at quickly increased production of biogas and showing superior results to other widely used additives as glycerol. Nevertheless, for easy and quick production material degradability of volatile acids, the addition of high concentrations of polymer is not indicated by the possibility of acidification of the reactors. / O aumento na geração e acúmulo de resíduos sólidos compostos principalmente por embalagens, acarretou uma busca por tecnologias de desenvolvimento de plásticos e filmes biodegradáveis passíveis de tratamento a partir de processos convencionais utilizados para materiais orgânicos. Atualmente, diversos plásticos, poliestireno expandido e filmes biodegradáveis, são produzidos das mais diversas formas, sendo que o presente trabalho visa avaliar principalmente a degradação anaeróbia de polímeros biodegradáveis à base de fécula de mandioca. A dissertação é dividida em dois capítulos sendo que o primeiro visa avaliar a digestão anaeróbia de polímero orgânico à base de fécula de mandioca diluído em água residual de suínos em diversas concentrações. Enquanto isso, o segundo capitulo tem por finalidade comparar o polímero biodegradável à base de mandioca com outro material largamente estudado como aditivo no processo de biodigestão, o glicerol. As utilizações de processos de biodigestão anaeróbia mostram-se eficientes na degradação e estabilização de materiais poliméricos a base de mandioca e garantem elevadas taxas de produção de biogás rico em metano, podendo ser utilizado com diversas finalidades energéticas, garantindo economia em processos produtivos. O polímero ainda pode ser considerado interessante aditivo em processos de digestão de outros resíduos agroindustriais visando-se rápido aumento da produção de biogás e apresentando resultados superiores a outros aditivos largamente empregados como o glicerol. Apesar disso, pela fácil degradabilidade do material e rápida produção de ácidos voláteis, a adição de altas concentrações de polímero não é indicada pela possibilidade de acidificação dos reatores

Os copolímeros de 3-hidroxibutirato e 3-hidroxihexanoato (P3HB-co-3HHx) são da família dos polihidroxialcanoatos (PHA), materiais termoplásticos e biodegradáveis acumulados por bactérias a partir de fontes de carbono renováveis. O P3HB-co-3HHx desperta interesse industrial para frações de 3HHx menores que 20 mol%, assemelhando-se ao polietileno de baixa densidade. Neste projeto, criou-se um sistema genético para controlar a composição do copolímero P3HB-co-3HHx pela indução de genes da biossíntese de precursores 3HB. Baseado no promotor lac foram construídas cinco versões do plasmídeo de controle de copolímero (pCC) utilizando o promotor Lac. Porém, mesmo com a versão mais aprimorada, não foi possível o controle de composição de P3HB-co-3HHx em Pseudomonas sp. LFM461. Através de experimentos de atividade enzimática e RT-qPCR do cDNA do gene phaA e phaB, foi possível indicar que o problema está na impossibilidade do promotor Lac de promover expressão dos genes de biossíntese de 3HB presentes nos pCC. / Polyhydroxyalkanoates (PHA) are polyesters material accumulated by bacteria which has thermoplastic and biodegradable proprieties and can be produced from renewable feedstocks. Copolymers of 3-hydroxybutirate and 3-hydroxyhexanoate (P3HB-co¬-3HHx) which contain less than 20mol% of 3HHx have being researched for its industrial proprieties. Recently, our laboratory has been researching a Pseudomonas sp. strain, LFM461, which can produce high 3HHx content when hosting PHA biosynthesis genes from Aeromonas. In this project, it was design a genetic system for control of P3HB-co-3HHX composition through induction of 3HB monomers biosynthesis. Thus, five versions of a copolymer control plasmid (pCC) was built based on Lac promoter. However, even through improvements on stability and expression profile of pCC it was not possible to stablish an assay of successful PHA composition control in Pseudomonas sp. LFM461. By enzymatic activity and RT-qPCR of cDNA experiments we have indications of problems of Lac promoter on driving the expression of 3HB genes in pCC.

Aliphatic polyesters such as polycaprolactone and polylactide have received more attention in recent years for their use in biomedical applications because of their biodegradable nature. These polymers are often synthesized using homogeneous metal complexes. Unfortunately, using homogeneous metals as catalysts leads to metal contamination in the product polymer, a result which is highly undesirable in a polymer intended for biomedical use. More recent work has shown that these polymers can be synthesized using homogeneous metal-free complexes. These catatlysts are generally less active than metal catalysts, and although they do not contaminate the polymer with metal residue, they are still difficult to recover and hence recycle for further use. In this work, we attempted to create a metal-free, silica-supported catalyst for use in the synthesis of polycaprolactone or polylactide. Ultimately, n-propylsulfonic acid-functionalized porous and nonporous silica materials are evaluated in the ring-opening polymerization of epsilon-caprolactone. All catalysts allow for the controlled polymerization of the monomer, producing polymers with controlled molecular weights and narrow polydispersities. Polymerization rates are low, with site-time-yields generally one to three orders of magnitude lower than metal-based systems. The catalysts are easily recovered from the polymerization solution after use and are shown to contain significant residual adsorbed polymer. Solvent extraction techniques are useful for removing most of the polymer, although the extracted solids are not effective catalysts in recycle experiments. These new materials represent a green alternative to traditional metal-based catalysts, as they are recoverable and leave no metal residues in the polymer.

The role of matrix metalloproteinase (MMP)-9 and processing conditions of biodegradable polymer scaffolds has been investigated to optimize engineering vascular constructs. For a small diameter vascular construct, uniform 10 mm thickness of highly porous scaffolds were developed using a computer-controlled knife coater and exploiting phase transition properties of salts. The comparative study of fast vs. slow degrading three-dimensional scaffolds using a fast degrading poly D, L-lactic-glycolic acid co-polymer (PLGA) and a slow degrading poly e-caprolactone (PCL) indicated that fast degradation negatively affects cell viability and migration into the scaffold in vitro and in vivo, which is likely due to the fast polymer degradation mediated acidification of the local environment. MMP-9 was crucial for collagen remodeling process by smooth muscle cells (SMC). MMP-9 deficiency dramatically decreased inflammatory cell invasion as well as capillary formation within the scaffolds implanted in vivo. This study reports that the angiogenic response developed within the scaffolds in vivo was related to the presence of inflammatory response. Combinatorial polymer libraries fabricated from blended PLGA and PCL and processed at gradient annealing temperatures were utilized to investigate polymeric interactions with SMC. Surface roughness was also found to correlate with SMC adhesion. SMC aggregation, proliferation, and protein production, were highest in regions that exhibited increased surface roughness, reduced hardness, and decreased crystallinity of the PCL-rich phases. This study revealed a previously unknown processing temperature and blending compositions for two well-known polymers, which optimized SMC interactions.

Currently growth plate fractures account for nearly 18.5% of fractures in children and can lead to stunted bone growth or angular deformation. If the body is unable to heal itself a bony bar forms, preventing normal bone growth. Clinical treatment involves removing the bony bar and replacing it with a filler substance, which causes poor results 60% of the time. Using primarily poly(lactic-co-glycolic acid) (PLGA) as the scaffold material, the goal was to develop an implant that would support to the implant site, allow for cell ingrowth, and degrade away over time. Porous scaffolds were fabricated from PLGA microspheres using the salt leaching method. The first part of this work investigated the effect of sintering the microspheres by studying the mechanical properties, degradation and morphology and their potential applications for hard and soft tissue implants. Growth factor or drugs can be encapsulated into PLGA microspheres, which was the second part of this work. Encapsulated insulin-like growth factor I (IGF-I) was able to withstand the scaffold fabrication process without compromising it’s bioactivity and promoted cell proliferation. The next part of this work experimented with the addition of a hydrogel porogen. Porogen particles were made using a quick degrading poly(beta-amino ester) (PBAE) hydrogel and loaded with ketoprofen. The addition of the porogen creates a dual drug-releasing scaffold with a localized delivery system. The final step of this work involved animal studies to determine the effectiveness of the scaffolds in growth plate regeneration and how they compare to the current clinical treatment option. Gross observation, microCT analysis, angular measurement of bone growth and histological methods were employed to evaluate the scaffolds. The goal was to develop a versatile scaffold that could be used for a wide range of tissue engineering applications. The mechanical properties, degradation profiles and drug delivery capabilities can be all tailored to meet the specific needs of an implant site. One specific application was regenerating the native growth plate that can also encourage the endogenous mesenchymal stem cells to follow the desire linage. By regenerating the native growth plate, angular deformation and stunted limb growth were greatly reduced.

In situ forming implants (ISIs) are popular due to their ease of use and local drug delivery potential, but they suffer from high initial drug burst, and release behavior is tied closely to solvent exchange and polymer properties. Additionally, such systems are traditionally viewed purely as drug delivery devices rather than potential scaffold materials due to their poor mechanical properties and minimal porosity. The aim of this research was to develop an injectable ISI with drug release, mechanical, and microstructural properties controlled by micro- and nanoparticle additives. First, an injectable ISI was developed with appropriate drug release kinetics for orthopedic applications. Poly(β-amino ester) (PBAE) microparticles were loaded with simvastatin or clodronate, and their loading efficiency and drug retention after washing was quantified. Drug-loaded PBAE microparticles and hydroxyapatite (HA) microparticles were added to a poly(lactic-co-glycolic acid) (PLGA)–based ISI. By loading simvastatin into PBAE microparticles, release was extended from 10 days to 30 days, and burst was reduced from 81% to 39%. Clodronate burst was reduced after addition of HA, but was unaffected by PBAE loading. Scaffold mass and porosity fluctuated as the scaffolds swelled and then degraded over 40 days. Next, the mechanical properties of these composite ISIs were quantified. Both micro- and nanoparticulate HA as well as PBAE microparticle content were varied. Increasing HA content generally improved compressive strength and modulus, with a plateau occurring at 30% nano-HA. Injectability remained clinically acceptable for up to 10% w/w PBAE microparticles. Ex vivo injections into trabecular bone improved both strength and modulus. Lastly, HA-free ISIs were investigated for drug delivery into the gingiva to treat periodontitis. Doxycycline and simvastatin were co-delivered, with delivery of doxycycline over 1 week accompanied by simvastatin release over 30 days. PBAE-containing ISIs exhibited higher initial and progressive porosity and accessible volume than PBAE-free ISIs over the course of degradation. Additionally, PBAE-containing ISIs provided superior tissue retention within a simulated periodontal pocket. The ISIs investigated here have a wide range of potential applications due to their flexible material and drug release properties, which can be controlled by both the chemistry and concentration of various particulate additives.

Breast cancer is the most frequent type of cancer seen in woman. Chemotherapy is one of the most important treatments for breast cancer. However, systemic toxicity, drug resistance and unstable kinetics of the drug in the blood are serious problems of chemotherapy. The use of biodegradable polymers for controlled release of anticancer drugs has gained popularity in recent years. Controlled release of anticancer drugs from polymeric carriers has some advantages such as improvement in the efficiency of treatment, reduction in systemic toxicity and prevention of the drug resistance that is developed by the cancer cells. In this study, it was aimed to prepare such a controlled release system for anticancer drugs which are used in breast cancer treatment by using biodegradable copolymer poly(D,L-lactide-co-glycolide) and to characterize in terms of morphology, size, drug content and drug release rate. In the first part of this study / empty and drug loaded poly (D,L-lactide-co-glycolide) microspheres were prepared. Two sets of empty poly(D,L-lactide-co-glycolide) microspheres were prepared by solvent evaporation technique with single emulsion (oil/water) to determine the effect of stirring rate on size of microspheres. Increase in stirring rate caused decrease in size of microspheres. Drug loaded poly(D,L-lactide-co-glycolide) microspheres were prepared for controlled release of anticancer drugs which are used in breast cancer treatment namely / 5-fluorouracil, methotrexate and tamoxifen by using solvent evaporation technique either with double emulsion (water/oil/water) or single emulsion (oil/water). In the second part of this study / empty and drug loaded microspheres were characterized. Inverted light microscopy and scanning electron microscopy were used to examine morphology and size of microspheres. Drug content of microspheres and amount of released drug were determined and drug release profile was obtained for each anticancer drug separetely.

Since the industrial revolution the rise of the global economy depends on using more amounts of fossil fuels. Currently oil is the leading feedstock for the production of various kinds of plastic products, from packaging materials to machine parts. However, even this advanced technology, such as plastic, awarded several Nobel prizes, has its drawbacks. The big disadvantage is their very slow degradation (tens to thousands of years), thereby the accumulation of waste is increasing. Another disadvantage is its production from non-renewable materials (oil). Therefore, the developed economies, including the European Union (EU), are trying to find new alternatives to conventional plastics using biotechnology manufacturers to called bioplastics, which are made from renewable materials. This thesis deals with the use of bioplastics in the market. Using the questionnaires is creating survey of market among producers of bioplastics and consumers, combined with a personal interview with the promoters of bioplastics. Results processed by this methodology showed that the biggest factor, which influence the promotion of bioplastics, is too high price. This is the main reason why the public is so little informed about them. If the price of production decreases, promotion and use of bioplastics will be probably to increase.

Charles University Faculty of Pharmacy in Hradcec Králové Department of Pharmaceutical Technology Supervisor: doc. RNDr. Milan Dittrich, CSc. Student: Simona Medviďová Title of thesis: Formulation and testing of branched polyesters siRNA-loaded nanoparticles The progression of development increases demand for new and more effective drug systems formulations. This diploma thesis is focused on the preparation of nanoparticles from biodegradable branched polyesters based on PLGA, which are suitable for the transport of an oligonucleotide of a small interfering nucleic acid, siRNA. The theoretical part focuses on the characteristics of usable polymers, their possible modifications, the methods of preparation with closer look at the selected nanoprecipitation method, the important parameters such as particles size, zeta potential, and polydispersity. The main part is also characterization of siRNA in terms of structure, properties, modifications, and its function. A more extensive experimental part deals with the appropriate choice of type and concentration of polyester and stabilizer, methods of preparation and characterization of nanoparticles, and the possibility of analyzing encapsulated siRNA. Chapters results and discussion compares polyesters branched on tripentaerythritol, and polyacrylic acid...

Charles University, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, Ph.D. Student: Michal Bárta Title of Thesis: Preparation of pharmaceutical nanoparticles: optimalization process Pharmaceutical, polymer nanoparticles besides others work as well as a drug carriers. Their uniqueness is not only because of their subcelular size, but as well because of the biodegradability and biocompatibility they hold. The benefit of these nanoparticiples is the possibility of creation of selective naoparticiples which are able to controle long-term release. The formulation of polymer nanoparticles can be reached within methods using preformed polymer or with polymerization of monomers. The main goal of my thesis was to optimize the production process of polymer nanoparticles and the observation of the solvent influences. The methods used for this reaserch were evaporation method and nanoprecipitation. Granulometric and electrical characteristics of particles were measured with Zetasizer ZS 90. Measurements have prooved, that it is preferable to use the nanoparticle method for the prepartion of the the small nanoparticles with low polydispersity and sufficient stability. From the results of the granulometric analysis of nanoparticles made by the...