A vida útil do filé de salmão fresco é em grande parte limitada pela deterioração microbiana, proteolítica e oxidativa. Esse trabalho visou estudar o efeito do filme de quitosana adicionado ou não do extrato de resíduo agroindustrial de pimenta rosa (Schinus terebinthifolius Raddi) sobre a vida útil e qualidade de salmão do Atlântico (Salmo salar) fresco, embalado em atmosfera modificada (AM, 100% CO2), durante 28 dias. Os filés de salmão (± 300 g) com 11 dias post mortem sem pele e sem ossos foram embalados em 100% de dióxido de carbono (CO2), submetidos aos tratamentos: sem filme (TC), com filme de quitosana (TFQ) e com filme de quitosana adicionado do extrato de resíduo agroindustrial de pimenta rosa (TFQPR), armazenados a 2 ± 1° C e sem exposição à luz por 0 (11 dias), 7, 14, 21 e 28 dias. Após cada período de armazenamento, nove bandejas de cada tratamento foram analisadas de acordo com parâmetros físico-químicos (pH, cor, capacidade de retenção de água (CRA), perfil de textura (PT), bases voláteis totais (BVT), trimetilamina (TMA), estabilidade oxidativa, perfil de ácidos graxos (PAG), degradação de ATP e seus catabólitos), microbiológicas (microrganismos aeróbios mesófilos e psicrotróficos, bactérias láticas, coliformes totais e termotolerantes) e sensoriais. O estudo foi conduzido por um delineamento inteiramente casualizado com arranjo fatorial (3 tratamentos x 5 tempos de armazenamento), considerado como parcela o filé de salmão embalado em atmosfera modificada, com 3 repetições. Os dados foram analisados no ambiente R, a fim de verificar o efeito de tempo, tratamento e tempo x tratamento. Durante o armazenamento, o pH oscilou para os três tratamentos. Observou-se a descoloração dos filés de salmão devido à oxidação dos carotenoides astaxantina e cantaxantina, presentes no músculo do pescado. Ao longo do armazenamento, CRA foi reduzida, influenciando no perfil de textura das amostras. Os filés de salmão tornaram-se mais macios devido à proteólise muscular e a ação de microrganismos deteriorantes presentes. Os dados de oxidação lipídica foram baixos e não influenciou no PAG do salmão - considerando que o salmão é uma boa fonte de ácidos graxos poli-insaturados da série ômega-3. Os microrganismos deteriorantes analisados aumentaram ao longo do armazenamento, porém não ultrapassaram os limites recomendados pela ICMSF, bem como a contagem dos microrganismos patógenos. A análise sensorial permitiu verificar as mudanças nos filés de salmão ao longo do armazenamento, porém não houve diferença significativa entre os tratamentos. Em conclusão, o filme ativo foi eficiente na manutenção da qualidade e vida útil dos filés de salmão embalados com AM durante 28 dias de armazenamento, em comparação com o grupo controle (TC). / Shelf-life of the fillet of fresh salmon is greatly limited by microbial, proteolytic and oxidative deterioration. This research aimed to study the effect of chitosan active films and the addition of agro-industrial residue of pink pepper (Schinus terebinthifolius Raddi) on this film on fresh Atlantic salmon (Salmo salar) shelf-life and quality packaged in modified atmosphere packaging (MAP, 100% CO2) during 28 days. Skinless and boneless salmon fillets (± 300 g) with 11 days post mortem were packaged in 100% carbon dioxide (CO2) MAP according to three treatments: without chitosan film (TC), with chitosan film (TFQ) and with chitosan film added with agro-industrial residue of pink pepper (TFQPR), stored at 2 ± 1° C and under dark condition for 0 (11 days),7, 14, 21, and 28 days. After each retail day, 9 trays of each treatment were analyzed according to physical-chemical (pH, color, water holding capacity (WHC), texture profile (TP), total volatile basic nitrogen (TVB-N), trimethylamine (TMA), oxidative stability, fatty acid profile (FAP), and ATP and ATP-catabolites quantification), microbiological (the content of mesophilic, psychrotrophic, lactic, thermotolerant bacteria and total coliform), and sensory parameters. This research used Completely Randomized Design (CRD) with a factorial arrangement (3 treatments x 5 five storage time), considering the packaged salmon fillet as a research unity, with 3 repetitions. Data was analyzed on R environment, in order to verify time, treatment and time x treatment effects. During storage, pH oscillated for the three treatments. The salmon fillets discolored due to the carotenoids astaxanthin and canthaxanthin oxidation, which are present in fish muscle. Along storage time, WHC reduced, influencing on sample texture profile. Salmon fillets softened, which is possibly resulting from muscle proteolysis and from spoilage bacteria action. Lipid oxidation data were low and did not influence on salmon FAP - considering that salmon is a good source of omega-3 poly-unsaturated fatty acid. Fish spoilage bacteria increased along storage, but it was not higher than the legal limit established by ICMSF, as well as pathogen bacteria. Sensory analysis revealed overall changing on salmon fillets during storage. In conclusion, active film was efficient in the maintenance of quality and shelf-life of MAP-packaged salmon fillets during 28 days of storage, compared to control group (TC).

Le chitosane présente des propriétés biologiques (biocompatibilité, biorésorbabilité, bioactivité) idéalement adaptées à des applications en ingénierie tissulaire. Dans cette étude partenariale (Programme ANR TECSAN 2010 ChitoArt), nous avons travaillé à l'élaboration d'hydrogels physiques de chitosane à propriétés physico-chimiques et biologiques variées et contrôlées, sans utilisation d'agents de réticulation externes. Ces hydrogels sont envisagés sous forme de tube mono ou pluri-membranaires pour une utilisation en tant que substituts vasculaires de petit diamètre (<6mm). En effet, l'ingénierie vasculaire présente, encore de nos jours, de nombreuses limitations lorsqu'il est question de vaisseaux de petits calibres. Notre démarche consiste en la modulation des paramètres structuraux (degré d'acétylation, masse molaire) et environnementaux (concentration du bain de gélification, du collodion) intervenants dans le procédé d'élaboration des hydrogels pour atteindre les critères physiques, biologiques et mécaniques compatibles avec cette application. L'étude morphologique des hydrogels par Cryo-Microscopie Électronique à Balayage (Cryo-MEB), via une méthode de préparation originale a permis une meilleure compréhension de l'organisation micro-structurale et multi-échelle des hydrogels de chitosane. Cette approche fondamentale a été couplée à une évaluation in vivo des propriétés biologiques des hydrogels ainsi qu'a des caractérisations mécaniques des substituts vasculaires. En particulier, l'évaluation de la suturabilité de nos substituts a mené au développement d'une formulation donnant lieu à des hydrogels physiques de chitosane suturables ayant fait l'objet d'un dépôt de brevet (N° de dépôt FR1363099). Le contrôle et la modulation des paramètres d'élaboration des hydrogels ont permis l'obtention de substituts vasculaire cellularisables et respectant les exigences (suture, compliance, résistance à l'éclatement) concernant leur implantation in vivo / Chitosan presents biological properties (biocompatibility, bioresorbability, bioactivity) ideally suited for tissue engineering. In this partnership study (ANR TECSAN 2010 ChitoArt program), we worked at the elaboration of physical chitosan hydrogels presenting various and controlled physicochemical and biological properties, without any external crosslinkers. These hydrogels are envisioned under mono- or poly-membranous tubes for small diameter vascular substitutes (<6mm) purposes. Indeed, vascular engineering presents, even today, numerous limitations for small calibre vessels. Our strategy consists in the modulation of both structural (degree of acetylation, molar mass) and environmental (neutralization bath and collodion composition and concentration) parameters involved in hydrogels elaboration process in order to reach physical, biological and mechanical requirements suitable for this application. The study of hydrogels morphology by Cryo-Scanning Electron Microscopy (Cryo-SEM), using an original sample preparation method led to a better comprehension of chitosan hydrogels fine structure and multi-scale organization. This fundamental approach was conducted through the in vivo biological evaluation of hydrogels but also to mechanical characterizations of vascular substitutes. In particular, our substitutes were evaluated in term of suture retention resulting in the development of a formulation that led to suturable physical chitosan hydrogels, which were protected by a patent (Deposit number: FR1363099). Hydrogels elaboration parameters control and modulation have resulted in the development of colonisable vascular substitutes matching their in vivo implantation requirements (suture retention, compliance, burst pressure)

Although millions of individuals worldwide are affected by blinding retinal degenerative diseases, most have very few options for treatment and no hope for vision restoration. Induced pluripotent stem cell (iPSC) replacement therapies represent a promising treatment option, but their effectiveness is limited by an overall lack of physical support for injected cells. Stem cell scaffolds can be used to provide this support by serving as an attachment platform for cells before, during, and after implantation. Thus, the design of polymer scaffolds with appropriate biochemistry, mechanical properties, and morphology is a critical step toward developing feasible stem cell therapies for blinding eye diseases. In this work, we aim to design a regenerative scaffold for the retina and determine the interplay among these three key design parameters. First, the feasibility of using a synthetic scaffold to grow and differentiate iPSCs to neural progenitor cells is demonstrated. The porous and degradable poly(lactic-co-glycolic acid) scaffolds employed were able to support a greater density of differentiating iPSCS than traditional tissue culture plastic. Additionally, the power of chitosan, a naturally occurring polymer, to overcome the toxic effects of copper nanoparticles is described. For two different cell types, various doses, and several time points, chitosan coated copper nanoparticles were significantly less toxic than non-coated particles. The mechanical properties of the human retina and the effects of aging and disease were also estimated using measurements of compressive modulus in animal models. In order to reach a range similar to native tissue, polymer mechanical properties were controlled using cross-linking density and surfactant templating. The influence of morphology was studied by inducing polymer structure changes via surfactant templating. Morphology significantly influenced water uptake and compressive modulus for both cross-linked poly(ethylene glycol) (PEG) and cross-linked chitosan hydrogels. Surfactant templating did not negatively affect the biocompatibility of PEG hydrogels and slightly improved the ability of chitosan hydrogels to support the growth and differentiation of iPSCs. Overall we have demonstrated the ability to tune polymer structure, mechanical properties, and biochemistry. These results add to the growing body of research aimed to understand and control cell/material interactions for biomaterial optimization.

Le traitement de la corrosion constitue un enjeu économique, environnemental et de sécurité sanitaire. Plus largement utilisée à l’échelle industrielle, la protection par revêtements consiste à isoler le métal du milieu agressif par une couche adhérente, continue et imperméable. Ils doivent répondre à trois propriétés majeures : 1) être fortement adhérent au substrat métallique, 2) posséder de bonnes propriétés barrière pour limiter la pénétration de l’eau et des espèces agressives et 3) apporter un rôle d’inhibition de la corrosion. Cependant, la protection des surfaces métalliques par les techniques actuelles génère une pollution notable liée à l’usage de chromates. L’utilisation de polymères biosourcés et solubles en milieu aqueux serait un challenge et contribuerait à préserver l’environnement. Les polysaccharides comme le chitosane sont des macromolécules biodégradables et respectueuses de l'environnement possédant des propriétés d’anticorrosion et sont donc des alternatives envisageables. Ces travaux de thèse portent sur le développement de revêtements anticorrosion à base de chitosane. Le chitosane possède deux points faibles pour être utilisé comme revêtement contre la corrosion : 1) une adhésion insuffisante sur la surface des matériaux et 2) un caractère hydrophile. En conséquence, le chitosane a été modifié chimiquement afin d’augmenter son adhésion et ses propriétés barrières. Afin d’améliorer son adhésion sur des substrats métalliques, des groupements de type acide phosphonique ont été ajoutés via la réaction de Kabachnik-Fields sur le chitosane. L’élaboration d’un chitosane possédant des fonctions catéchol a été également discutée. Dans un premier temps, le chitosane modifié a été testé et caractérisé par spectroscopie d’impédance électrochimique (SIE) en tant qu’inhibiteur de corrosion puis des revêtements à partir de ce même chitosane ont été réalisés et leurs protections contre la corrosion ont été évaluées. Deux approches de mise en forme des revêtements ont été testées : par dip-coating et par la technique Layer-by-Layer (LbL). Différentes voies de fonctionnalisation du chitosane ont également été présenté afin d’augmenter les propriétés barrière du revêtement. La chimie de phthaloylation du chitosane a été décrite puis le greffage de chaînes hydrophobes a été étudié. / Corrosion treatment is an economic, environmental and health safety issue. More widely used on an industrial scale, coating protection consists in isolating the metal from the aggressive medium by an adherent, continuous and impermeable layer. They must have three major properties: 1) be strongly adherent to the metallic substrate, 2) have good barrier properties to limit the penetration of water and aggressive species and 3) provide a role in inhibiting corrosion. However, the protection of metal surfaces by current techniques generates significant pollution due to the use of chromates. The use of bio-based and soluble polymers in aqueous media would be a challenge and would contribute to preserving the environment. Polysaccharides such as chitosan are biodegradable and environmentally friendly macromolecules with anticorrosive properties and are therefore possible alternatives. These theses focus on the development of anticorrosion coatings based on chitosan. Chitosan has two weak points for use as a coating against corrosion: 1) insufficient adhesion on the surface of the materials and 2) hydrophilicity. As a result, chitosan has been chemically modified to increase its adhesion and barrier properties. In order to improve its adhesion on metal substrates, phosphonic acid groups have been added via the Kabachnik-Fields reaction on chitosan. The development of a chitosan with catechol functions was also discussed. Initially, the modified chitosan was tested and characterized by electrochemical impedance spectroscopy (EIS) as a corrosion inhibitor and coatings based on the same chitosan were made and their corrosion protection evaluated. Two approaches of coating elaborations were tested: dip-coating and Layer-by-Layer (LbL). Different ways of functionalizing chitosan have also been presented to increase the barrier properties of the coating. Phthaloylation chemistry of chitosan was described and hydrophobic chain grafting was studied.

The presented diploma thesis deals with a targeted modification of the structural properties of hydrogels, which is closely related to the application properties of these materials (eg transport). Due to the desired pharmacological applications of the use of these materials for targeted drug release, hydrogels based on chitosan and polyvinyl alcohol as substances with good biocompatibility were selected for the study. The combination of these polymers ensured swelling (controlled by the presence of chitosan) and viscoelastic (influenced by the presence of polyvinyl alcohol) properties, which were characterized by a wide range of analytical and physicochemical methods (swelling, tensile strength, rheology, atomic force microscopy or specific surface area, etc.). Information on structural properties played a crucial role not only for a detailed description of the studied materials in terms of whether the structural properties can be changed in a targeted manner, but also served as an explanation for the different release of the active substance diclofenac from the hydrogel matrix. With regard to the literature search, the effect of pH and crosslinking was chosen to modify the properties. From the measured results it was found that even a slight change in pH has an effect on the transport or release of the active substance. The results obtained in this work may be useful in the formation of hydrogel matrices with drugs depending on the intended medical applications.

This diploma thesis deals with application of microencapsulation techniques in development of hydrogel controlled-release systems in which the main role is played by humic acids, biopolymer chitosan, compound fertilizer NPK and 3-indoleacetic acid. This paper continues my bachelor thesis topic about utilization of polyelectrolyte complexes. The aim of this work was to develop a literature review focusing on the microencapsulation techniques and according to its results optimize the method. Microencapsulation was performed with a commercial encapsulator BUSCHI B-395 Pro and a release of individual components into a water was measured. An amout of released substances was measured by UV-VIS method and HPLC analysis. Practical part also included testing of repeated swelling and drying. It was found that suitable composition and combination of ingredients form hydrogels for further use in agriculture.

Ce projet vise à proposer des nouveaux candidats médicaments pour lutter contre les infections parasitaires cutanéo-muqueuses qui représentent un problème de santé majeur. C’est notamment le cas de la Trichomonose urogénitale et la leishmaniose cutanée.Malheureusement, l’administration systémique de première intention par le métronidazole (MTZ) pour traiter la trichomonose urogéntitale occasionne des problèmes de résistances et des effets secondaires indésirables. Ainsi, nous avons développé de nouvelles stratégies thérapeutiques en ciblant à la fois les mécanismes pharmacologiques et physiques de l’infection par Trichomonas vaginalis. Après avoir réussi à augmenter la solubilité apparente du MTZ dans l’eau en utilisant une beta-cyclodextrine méthylée, nous l’avons formulé dans un hydrogel thermosensible et mucoadhésif composé de pluronic® F127 et d’un biopolymère cationique et mucoadhésif, le chitosane. Cette formulation est spécifiquement adaptée à une application topique tout en offrant un contrôle de la libération du MTZ et une réduction de son passage systémique à travers la muqueuse vaginale. La viscosité élevée de l’hydrogel à température corporelle nous a conduit à étudier son effet sur la mobilité du protozoaire Trichomonas vaginalis. Il s’agit d’une stratégie physique d’immobilisation du parasite en parallèle à la chimiothérapie par le MTZ. Le suivi des trajectoires des parasites par vidéo-microscopie a montré la capacité de l’hydrogel seul ou en association avec le chitosane à immobiliser complètement T. vaginalis et à inhiber son attachement à la muqueuse. Ces évaluations ont été réalisées chez la souris. Cependant, le chitosane seul n’a pas permis d’immobilier les parasites et n’a pas montré une activité anti-T. vaginalis propre. Dans ce contexte, nous nous sommes inspirés des travaux antérieurs menés par notre équipe sur le développement de formulations à base de chitosane, et plus particulièrement des nanoparticules (NPs) composées de poly(isobutylcyanoacrylates) recouvertes de chitosane. Ces NPs ont une activité trichomonacide propre, même sans rajouter des substances actives, alors que des NPs sans chitosane étaient inactives. Nous avons étudié le mécanisme d’action et nous avons montré une meilleure internalisation des NPs lorsqu’elles étaient recouvertes de chitosane. Ces NPs ont provoqué des altérations morphologiques drastiques de la membrane du parasite. Cette activité pourrait être due en partie à l’interaction électrostatique entre la surface de T. vaginalis chargée négativement et les NPs recouvertes de chitosane cationique.Dans le but d’élargir le champ des applications de ces NPs à d’autres parasites, nous nous sommes intéressés à l’évaluation de leur effet anti-leishmanien vis-à-vis de Leishmania major. En effet, le chitosane connu pour ces propriétés cicatrisantes nous a paru particulièrement adapté pour cette pathologie. Nous avons ainsi montré in vitro et in vivo que les NPs recouvertes de chitosane avaient une activité anti-L. major propre, sans ajouter de substances actives. Dans un deuxième temps, nous avons décidé de nous orienter vers des particules de formes allongées et d’évaluer leur activité anti-leishmanienne. Ces particules appelées « plaquettes » sont constituées d’assemblages de chitosane hydrophobisé avec l’acide oléique et l’alpha-cyclodextrine dans l’eau. Cette stratégie nous a paru intéressante pour améliorer l’interaction des plaquettes avec la membrane de L. major, vue que ces parasites sont également de morphologie non-sphérique. Les résultats histologiques et immunohistochimiques des lésions cutanées ont montré une diminution significative du granulome inflammatoire et une réduction de la charge parasitaire par rapport à l'amphotéricine B seule utilisée comme référence.En conclusion, au cours de cette thèse, plusieurs formulations ont été développées et ont montré des efficacités biologiques en agissant sur des mécanismes pharmacologiques et/ou physiques des parasites. / This project aims at developing new therapeutic strategies against parasitic muco-cutaneous infections such as urogenital trichomonosis and cutaneous leishmaniasis which still represents a major health problem worldwide.Unfortunately, metronidazole (MTZ) is a first-line systemic treatment for urogenital trichomoniasis that causes resistance and side effects. We have thus developed new strategies by acting on both the pharmacological and the physical mechanisms of Trichomonas vaginalis infection. After a successfull increase of the apparent solubility of MTZ in water using a methylated -cyclodextrin, we formulated it in a thermosensitive and mucoadhesive hydrogel composed of pluronic® F127 and a cationic and mucoadhesive biopolymer, chitosan. This formulation is specifically adapted for topical application providing a control of MTZ release and reduction of its systemic passage through the vaginal mucosa.Then, the ability of the high viscosity hydrogel to immobilize T. vaginalis was investigated by video-microscopy. Monitoring the trajectories of each parasite by multiple particle tracking showed the ability of the hydrogel alone or in combination with chitosan to completely immobilize T. vaginalis and to inhibit parasite attachment to the mucosa. These evaluations were performed on mice experimental model. However, chitosan alone did not allow parasite immobilization and did not show any anti-T. vaginalis activity. In this context, we were inspired by previous works conducted by our team on the development of formulations based on chitosan, and more particularly nanoparticles (NPs) composed of poly(isobutylcyanoacrylates) coated with chitosan. These NPs have their own trichomonacidal activity, even without adding active substances, while NPs without chitosan were inactive. Investigated of the mechanism of the activity showed better internalization of NPs when coated with chitosan. These NPs caused drastic morphological alterations on the parasite membrane. This activity could be due to the electrostatic interaction between negatively charged T. vaginalis surface and cationic chitosan coated NPs.In order to broaden the applications of these NPs to other parasites, we were interested in evaluating the anti-L. major activity of NPs coated or not with chitosan. Indeed, chitosan known for its healing properties could be particularly adapted for this pathology. We thus showed in vitro and in vivo that NPs coated with chitosan had intrinsic anti-L. major activity without adding any drug. In a second step, we decided to design chitosan elongated particles and to evaluate their anti-leishmanial activity. These particles called "platelets" are composed of chitosan hydrophobically-modified with oleic acid and cyclodextrin in water. This strategy could be interesting to improve the interaction of platelets with the L. major membrane, as these parasites had also non-spherical morphology. The histological and immunohistochemical results of skin lesions showed a significant decrease in inflammatory granuloma and a reduction in parasitic load compared with amphotericin B alone, used as a reference.In conclusion, during this thesis, several formulations were developed and showed biological activities by acting on pharmacological and/or physical mechanisms of the parasites.

Orientador: Luiz Francisco Malmonge / Resumo: Os fertilizantes de liberação modificada têm conquistado âmbitos cada vez maiores nas pesquisas e em utilizações agrícolas devido a suas principais características de menores perdas de nutrientes e por seu menor custo, que envolve menos aplicações no campo e menores quantidades de fertilizantes utilizados, comparado aos fertilizantes convencionais. Este trabalho teve como objetivo elaborar fertilizantes com possível comportamento de liberação modificada, através da incorporação do fosfato de potássio monobásico (KH2PO4) no polímero quitosana, contribuindo, dessa forma, com as três fontes de nutrientes primários essenciais requeridos pelas plantas: nitrogênio, fósforo e potássio, por apenas dois recursos. Foram elaboradas duas amostras diferentes para posterior comparação, análise e aplicação. Os métodos utilizados no preparo das amostras foram: gotejamento em solução básica coagulante e casting. Foram feitas soluções de 8% de quitosana (m/v) dissolvidas em soluções de 5% de ácido acético, e subsequentemente foi adicionado o KH2PO4 (em diferentes concentrações para análise e para aplicação agrícola, foi usada a concentração de 60% (m/m) em relação à massa de quitosana). Foram feitas Microscopia eletrônica de varredura (MEV) para análise morfológica das amostras, Energia dispersiva de raios-X (EDX) para constatação dos elementos contidos nas amostras, o estudo da liberação dos nutrientes em solução aquosa (em pHs 5,4 e 6,7) e por fim, as amostras foram aplicadas em mudas de alf... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Modified-release fertilizers have been increasingly used in research and in agricultural uses due to their main characteristics of lower nutrient losses and their lower cost, which involves fewer applications in the field and less quantities of utilized fertilizers, compared to the conventional ones. This work aimed to elaborate fertilizers with possible modified release behavior, through the incorporation of monobasic potassium phosphate (KH2PO4) in the chitosan polymer, thus contributing with the three sources of essential primary nutrients required by plants: nitrogen, phosphorus and potassium, from only two resources. Two different samples were prepared for later comparison, analysis and application. The methods used in preparing the samples were: dripping in a basic coagulant solution and casting. Solutions of 8% chitosan (w/v) were prepared dissolved in solutions of 5% acetic acid, and subsequently KH2PO4 was added (in different concentrations for analysis and for agricultural application, the concentration of 60% (w/w) in relation to the chitosan mass). Scanning electron microscopy (SEM) was performed for the morphological analysis of the samples, energy dispersive X ray (EDX) to verify the elements contained in the samples, the study of the release of nutrients in aqueous solution (at pH 5.4 and 6, 7) and finally, the samples were applied to lettuce seedlings for comparative effect and material efficiency. The results of the EDX spectra showed that in the samples made... (Complete abstract click electronic access below) / Mestre

>Magister Scientiae - MSc / Peptides are among the main drugs which attract much attention because of their great potential in treating sexually transmitted diseases and other chronic diseases. There has been a major challenge of delivering these drugs in mucosal sites with low pH environment. The aim of this study is to synthesize acidic pH stable peptide loaded chitosan nanoparticles gels that could penetrate mucus layers covering the epithelial cells and kill HIV virus. Chitosan nanoparticles were synthesized by crosslinking method called Ionic gelation with Sodium tripolyphosphateTPP. / 2023

Fibers are classified into two groups; natural fibers and man-made fibers (MMF). There are three kinds of MMF: those made by transformation of natural polymers, those made from synthetic polymers and those made from inorganic material. Chitosan is classified as a biobased polymer and can be spun into man-made fibers. Due to its various functions, including anti-microbial, biocompatibility, biodegradability, metal-chelating, metal ions-coupling properties and general high molecular affinity, much attention has been paid recently to include chitosan into various concepts. The overall aim of this master thesis was to investigate the possibilities to make an antibacterial paper. Because chitosan contain primary amino groups that are cationic under mildly acidic conditions, it has antibacterial properties. Lab scale spinning of chitosan filaments was attempted in order to produce chitosan staple fibers that could be mixed with pulp fibers to make paper with antibacterial properties. Spinning methods used for a particular polymer is determined by the characteristics of the polymer. In the development of chitosan spinning at laboratory scale three different spinning methods were tested. A successful filament was produced by dry wet spinning. The filament was superior to the others in terms of dope composition and weight ratio of chitosan/acetic acid for protonation of the amino groups. Furthermore, the addition of glycerol improved the swelling of the chitosan hydrogel (or dope). Moreover, the condition of the coagulation step resulted in a good solidified filament with satisfactory elasticity and strength to be able to be taken up by a drawing cylinder. However, too small amounts of chitosan were produced in the development of chitosan spinning at lab scale and for production of antibacterial paper of chitosan. A second option was melt spinning of polylactide (PLA) filaments containing various amounts of chitosan. In this case PLA act as a carrier of chitosan into the paper sheet. Continuous filaments were spun in a sufficient amount. The antibacterial activity of PLA/chitosan fibers on E. coli bacteria was tested both on PLA/chitosan fibers as well as on suspensions. Under nutrient free conditions weak antibacterial effects was observed both for fibers and suspensions. However, in a more nutrient rich environment no effect was observed. This suggests that the produced fibers only had a weak antibacterial activity. To my knowledge the use of PLA in fiber form to carry chitosan into paper has not been attempted previously although different approaches to use chitosan as e.g. wound dressing is well described. In conclusion, there is a possibility to produce man made biodegradable fibers using chitosan and PLA that potentially could be added to paper. This paper might exert antibacterial properties that could have an interest to the market, e.g. for cleaning, in hospitals, and in the food industry.