Apesar da existência de uma quimioterapia, a tuberculose (TB) ainda permanece como uma das principais causas de mortalidade no mundo, especialmente nos países em desenvolvimento, em grande parte devido à epidemia da AIDS. Geralmente, a atual terapia da TB é eficiente, no entanto, ela implica em um longo tratamento com efeitos colaterais não desejáveis e consequentemente com pouca adesão. Tem sido relatada uma crescente incidência de cepas de Mycobacterium tuberculosis resistentes a múltiplos fármacos, sendo que uma das maiores razões para isso é a terapia ineficaz, provavelmente devido à carência na adesão. Portanto, a busca por novos fármacos e com o desenvolvimento de uma terapia eficiente para a TB, que aumente a adesão do paciente e reduza o surgimento de cepas resistentes á múltiplos fármacos é muito importante. A microencapsulação pode ser usada de forma segura para a liberação sistêmica de fármacos e também para direcionar a ação para o sítio de infecção. Dessa forma, um análogo sintético de neolignana (ASN) que apresentou destacada aitividade in vitro contra o M. tuberculosis foi encapsulado em micropartículas de co-polímeros do ácido lático e glicólico (PLGA) para a liberação sustentada deste composto. Tipos diferentes de micropartículas de PLGA contendo este fármaco foram desenvolvidas pela técnica de evaporação de solvente e posteriormente, elas foram avaliadas. A formulação contendo o ASN que exibiu a melhor eficiência de encapsulação e também demonstrou uma liberação sustentada foi verificada em um modelo de camundongo infectado com TB. O tratamento com as formulações de micropartículas resultou em uma depuração dos bacilos comparado aos controles. Além disso, os resultados da análise de cortes histológicos sugerem que estas formulações não induzem a nenhuma hepatotoxicidade. Estes resultados demonstraram a possibilidade de se usar formulações de micropartículas contendo o ASN para a obtenção de resultados efetivos em modelos murinos de TB, e indicaram o potencial do ASN como um novo fármaco antimicobacteriano. / Despite the existence of chemotherapy, tuberculosis (TB) still remains a leading cause of mortality of worldwide, especially in the developing countries, in part due to the AIDS epidemic. Current therapy of TB is generally effective, however, it involves a long course of treatment with unwanted side effects and consequently with poor compliance. An increasing incidence of multiple-drug-resistant strains of Mycobacterium tuberculosis (MDR-TB) has been related and one of the major reasons for this is inefficient therapy, probably due to lack of compliance. Thus, it is very important to search for new drugs with a development of an effective therapy for TB that improves patient compliance and reduces the emergency of MDR-TB. Microencapsulation technology can be used to safely deliver drugs systemically and target drugs to the site of infection. In this way, a synthetic analogue of a neolignan (SAN) that had a remarkable in vitro activity against M. tuberculosis was entrapped in poly (D,L-lactide-co-glycolide) (PLGA) microparticles for sustained delivery of this compound. Different types of PLGA microparticles containing this drug were developed by the solvent evaporation technique and then they were evaluated. A microparticle formulation containing the SAN that exhibited the best entrapment efficiency and also showed a sustained release was assessed in an infect mouse model of TB. Treatment with the microparticles formulation resulted in a clereance of bacilli compared to the controls. Besides that, results suggest that these formulations do not induce any hepatotoxicity on a histopathology basis. These results demonstrated the ability to use microparticles formulations containing SAN to achieve effective results in a murine TB model and indicate the potencial of SAN as a novel antimycobacterial drug.

Tem sido sugerido que um adequado reparo ósseo pode ser obtido por biomateriais híbridos, produzidos pela combinação de células e materiais substitutos ósseos macroporosos. O objetivo geral do presente estudo foi avaliar a aplicação do biomaterial híbrido formado pelo arcabouço de PLGA/CaP e células-tronco mesenquimais e osteoblastos derivados de medula óssea na engenharia de tecido ósseo. Para verificar qual o tamanho de poro deste arcabouço é mais adequado para este fim, foram realizados experimentos in vitro, que avaliaram a proliferação celular, atividade de fosfatase alcalina (ALP) e expressão quantitativa de genes marcadores do fenótipo osteoblástico em células cultivadas sobre os arcabouços; e in vivo, que avaliaram a formação óssea após implantação do arcabouço em defeitos ósseos críticos de calvária de ratos. Também foi avaliado o efeito do tamanho dos poros sobre o carreamento celular através da força centrifuga. Para avaliar o efeito do soro fetal bovino, utilizado na suplementação do meio de cultura celular, na resposta tecidual in vivo, arcabouços expostos ao soro foram implantados em defeitos ósseos críticos de calvária de ratos. O efeito da retirada do soro fetal bovino do meio de cultura sobre osteoblastos foi analisado através da proliferação celular, atividade de ALP, conteúdo de proteína total e mineralização. Para avaliar o efeito do estágio de diferenciação celular sobre a formação óssea, células em diferentes estágios de diferenciação osteoblástica associadas ao arcabouço de PLGA/CaP foram implantadas de forma autóloga em defeitos ósseos críticos de calvária de ratos. Arcabouços com tamanhos de poros de aproximadamente 1000 µm promovem maior diferenciação osteoblástica e melhor carreamento celular, enquanto arcabouços com poros de aproximadamente 500 µm promovem maior formação óssea e vascular in vivo. O soro fetal bovino influenciou negativamente a resposta tecidual e a formação óssea. A retirada do soro fetal bovino do meio de cultura reduziu a proliferação celular e a atividade de ALP sem afetar o conteúdo de proteína total e a formação de matriz mineralizada. Células-tronco mesenquimais indiferenciadas e em fase inicial de diferenciação osteoblástica (7 dias) promoveram maior formação óssea, portanto permitiriam a obtenção de um biomaterial híbrido com maior potencial osteogênico. / It has been suggested that an adequate bone repair can be obtained by hybrid biomaterials, produced by combining osteoprogenitor cells and macroporous bone substitutes. The aim of this study was to evaluate the application of hybrid biomaterial formed by PLGA/CaP scaffold and bone marrow-derived mesenchymal stem cells and osteoblasts in bone tissue engineering. The effect of scaffold pore size was evaluated in vitro assessing cell growth, alkaline phosphatase (ALP) activity, and quantitative gene expression of osteoblastic phenotype markers in osteoblasts cultured on scaffolds; and in vivo assesseing bone formation after implantation of scaffolds in critical size rat calvaria defects. It was also evaluated the effect of pore size on cell seeding by centrifugal force. To evaluate the effect of fetal calf serum used to supplement the cell culture medium on in vivo tissue response, scaffolds exposed to serum were implanted in critical size rat calvaria defects. The effect of withdrawal of fetal calf serum in the culture medium on osteoblasts was analyzed by cell growth, ALP activity, total protein content and mineralization. To evaluate the effect of cell differentiation stage on bone repair, cells either undifferentiated or in different stages of osteoblast differentiation associated with the PLGA/CaP were implanted autologously in critical size rat calvaria. Scaffolds with pore sizes of around 1000 µm would favor the osteoblast differentiation and display a better cell seeding, while the scaffolds with pore sizes of around 500 µm would favor increased bone and vascular formation. The fetal calf serum influenced negatively the in vivo tissue response and bone formation. The withdrawal of fetal calf serum in the culture medium reduced cell growth and ALP activity without affecting the total protein content and the formation of mineralized matrix Mesenchymal stem cells and osteoblats at the early stage of differentiation (7 days) promoted greater bone formation, therefore they would allow the obtention of a hybrid biomaterial with higher osteogenic potential.

Orientador: Francisco Benedito Teixeira Pessine / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-19T02:12:00Z (GMT). No. of bitstreams: 1 Calderini_Adriana_D.pdf: 8667238 bytes, checksum: 93c066670f54801635af79d770afae4c (MD5) Previous issue date: 2011 / Resumo: 5-Fluorouracil (5-FU) e um dos fármacos mais úteis no tratamento de tumores sólidos em adultos, especificamente carcinomas do trato gastrointestinal (estômago, cólon e reto) e da mama. Em resumo, seu maior efeito bioquímico e a inibição da síntese do DNA, pois a concentração que inibe sua síntese pode ainda permitir a sintese do RNA. Causa severos efeitos adversos como mielo supressão, mucosite, dermatite, diarréia e toxicidade cardíaca. Em razão disto, têm sido realizadas várias tentativas para encapsular 5-FU a fim de reduzir os efeitos adversos que ele provoca. O objetivo deste projeto foi encapsular este anti-neoplásico utilizando nano-esferas de ácido poli(lático-co-glicólico), PLGA, como sistema carreador, acoplando à sua superfície quitosana e folato de quitosana para melhor endereçamento aos locais de ação, bioadesividade e menor toxicidade. A encapsulação de 5-FU em nano-esferas de PLGA foi aperfeiçoada através de planejamento experimental e por análise quimiométrica. Muitos fatores foram estudados: métodos de preparação, temperatura, quantidade inicial de 5-FU e pH. Na caracterização destes sistemas foram utilizadas diversas técnicas: espalhamento dinâmico de luz, determinação do potencial Zeta, calorimetria diferencial de varredura, análise termogravimétrica, difratometria de raios-X e microscopia eletrônica de varredura. Além disso, foram realizados ensaios de perfil de liberação, de estabilidade coloidal e estudo do comportamento desses sistemas em relação às células in vitro. O planejamento experimental permitiu obter nanoparticulas com capacidade de carregamento em torno de 11% e eficiência de encapsulação de 32%. O acoplamento de quitosana e folato de quitosana permitiu retardar a liberação do fármaco em solução. Para armazenagem destas partículas, observou-se que elas foram menos degradadas quando estão liofilizadas e mantidas a 4 °C. A melhor concentração de sacarose para liofilizá-las, sem que ocorra aumento de tamanho e polidispersão, foi 250 mmol/L. Os testes in vitro comprovaram a eficácia destas formulações / Abstract: 5-fluorouracil (5-fluoro-1H-pyrimidine-2,4-dione) is one of the most used drug to treat solid tumors in adults, specifically gastrointestinal (stomach and colorectal) and breast carcinomas. In summary, the major biochemical effect of 5-FU is inhibition of DNA synthesis, since concentrations which inhibit this synthesis may still permit RNA synthesis. It causes severe adverse effects as myelosuppression, mucositis, dermatitis, diarrhea and cardiac toxicity. Its encapsulation in nanoparticles can reduce these adverse effects, prolong its release and the drug can be placed directly on its site of action. The goal of this work was to encapsulate this anti-neoplasic drug using poly (lactic-co-glycolic acid) PLGA nanospheres as carrier system, attaching on their surface chitosan and folate-chitosan to attain an enhanced targeting, bioadesivity and less toxicity. The encapsulation of 5-FU in PLGA nanospheres was improved through an experimental design and chemometry. Many factors were studied: methods of preparation, temperature, initial amount of 5-FU and pH. In the characterization, many techniques were employed: dynamic light scattering, determination of Zeta potential, differential scanning calorimetry, thermo gravimetric analysis, X-ray difractometry and scanning electron microscopy. Besides, we also analyzed the release profile, colloidal stability and the behavior of these systems in relation to in vitro cancer cells. The experimental design allowed obtaining nanoparticles with drug loading around 11% and encapsulation efficiency of 32%. The attachment of chitosan and folate-chitosan also allowed prolonging the drug release in solution. To store these formulations, we observed that lyophilized particles kept at 4 °C were less degraded. The best sucrose concentration to freeze-drying these particles with no size and polidispersity change was 250 mmol/L. The in vitro tests proved the efficacy of these formulations / Doutorado / Físico-Química / Doutor em Ciências

L'objectif poursuivi au cours de ce travail est l'élaboration de nanoparticules biocompatibles à visée diagnostique (IRM) et thérapeutique (PDT). Dans ce but, un protocole de nanoprécipitation a été optimisé pour obtenir de façon quantitative et reproductible, des nanoparticules de PLGA de diamètre compatible avec une injection par voie parentérale. Cette formulation a été employée avec succès pour l'encapsulation d'un chélate lipophile de Gd(III), pour l'encapsulation d'un photosensibilisateur (m-THPC) et pour la co-encapsulation de ces deux substances actives. Les formulations optimales permettent d'obtenir des efficacités d'encapsulation de 7 et 46 % en chélate de gadolinium et m-THPC respectivement. La cytotoxicité et la photocytotoxicité des GdDO3AC12-mTHPC@PLGA ont été testées sur deux lignées cellulaires (C6 et fibroblastes) et les résultats obtenus montrent que les propriétés photocytotoxiques du m-THPC sont maintenues après l'encapsulation. L'efficacité IRM de ces nanoparticules a aussi été évaluée et les mesures NMRD et IRM à 3T montrent que l'encapsulation des chélates de gadolinium améliore leur capacité à générer un contraste en mode T1 et donc la qualité des images. / This work aimed at the synthesis of biocompatible nanoparticles for PDT and MRI applications. To reach this goal, a nanoprecipitation technique was optimized using only biocompatible starting materials. This technique allowed the preparation, in a reproducible and quantitative manner of PLGA nanoparticles, compatible with parenteral injections. This formulation was successfully applied to encapsulate a lipophilic Gd(III) chelate, a photosensitizer (m-THPC) and to co-encapsulate these two substances. Optimal formulations showed encapsulation yields of 7 and 46 % for the gadolinium chelate and m-THPC, respectively. Cytotoxicity and photocytotoxicity experiments performed for two different cell lines (C6 cells and fibroblasts) incubated with GdDO3AC12-mTHPC@PLGA nanoparticles showed that m-THPC photocytotoxicity was maintained after its encapsulation. MRI efficacy of GdDO3AC12-mTHPC@PLGA nanoparticles was also evaluated by NMRD measurements and 3T MRI images. The corresponding results indicated that gadolinium chelate encapsulation improved its tendency to generate an efficient T1 contrast and consequently, enhanced the image contrast.

Dans ce travail de thèse, nous avons préparées des émulsions de Pickering innovantes, stabilisées par des nanoparticules (NP) biocompatibles et biodégradables de poly (acide lactique-co-glycolique) (PLGA), en utilisant du Miglyol comme phase huileuse. Ces systèmes permettent de s’affranchir de l’ajout de tensioactifs synthétiques, utilisés pour stabiliser les émulsions classiques, et qui sont souvent à l’origine d’irritations lors de traitements topiques chroniques. Dans ces émulsions ont été co-encapsulées deux substances actives, la première, un agent immunosuppresseur, dans les NP PLGA, la seconde, un agent anti-inflammatoire, dans les gouttelettes de Miglyol.Dans un premier temps, une étude physicochimique approndie a permis de mieux comprendre les mécanismes de stabilisation de ces émulsions, en fonction du type de NP utilisé. Aussi, l’influence de l’ajout de substances actives a été évaluée sur les structures macroscopique, microscopique et interfaciale des émulsions, mais également sur leur stabilité. Dans un deuxième temps, nous avons démontré que l’ajout de Carbopol, un polymère épaississant, permettait d’améliorer la stabilité, la texture et le pH des émulsions. Enfin, le potentiel thérapeutique d’un tel système à été évalué de manière préliminaire, notamment sa cytotoxicité sur des cultures de kératinocytes, mais aussi son activité immunosuppressive sur des cellules immunitaires activées et leur production de cytokines. Un tel système peut donc s’avérer intéressant pour le traitement de pathologies cutanées chroniques. / In this thesis work, we formulated innovative Pickering emulsions, stabilized by biocompatible and biodegradable poly (lactic-co-glycolic acid) nanoparticles (NP), using Miglyol as the oil phase. These systems could be an alternative to conventional emulsions, often stabilized with synthetic surfactants that can be responsible for irritation in particular during long-term topical treatments. Two active pharmaceutical ingredients (API) were successfully co-encapsulated, the first one, an immunosuppressant agent, entrapped in PLGA NP, the second one, an anti-inflammatory agent, incorporated in Miglyol droplets.Firstly, a thorough physicochemical characterization allowed to better understand the stabilization mechanism of these emulsions, depending on the type of NP used. Moreover, the influence of the addition of API was evaluated on the macroscopic, microscopic and interfacial structures of the emulsions, also on their stability. Secondly, we demonstrated that the addition of Carbopol, a thickening agent, improved the stability, texture and pH of emulsions. Finally, the therapeutic potential of such system was investigated through preliminary evaluation of its cytotoxicity on keratinocyte cells, but also its immunosuppressive activity on activated immune cells and their cytokine production. Such a system could be interesting for the treatment of chronical skin diseases.

Dans ce travail de thèse, nous avons formulé des émulsions de Pickering stables, biodégradables et biocompatibles stabilisées par des nanoparticules (NPs) de poly(acide lactique-co-glycolique) (PLGA). De telles émulsions sont une alternative, potentiellement moins toxique et irritante, aux émulsions conventionnelles stabilisées par des tensioactifs synthétiques. Dans un premier temps, une étude physico-chimique approfondie de ces systèmes a permis de clarifier leurs structures (macroscopique, microscopique et interfaciale) ainsi que leurs mécanismes et leurs cinétiques de stabilisation. Des études de la contribution du polymère stabilisant les NPs et des caractéristiques du polymère de PLGA utilisé sur les propriétés des émulsions ont également été réalisées. Cela a permis de mieux identifier les paramètres physico-chimiques clés nécessaires à une bonne stabilisation. Dans un second temps, nous nous sommes intéressés au potentiel pharmaceutique de ces émulsions pour une application topique. Des substances actives (SA), utilisées pour le traitement du psoriasis, ont été encapsulées avec succès dans les NPs (ciclosporine A et tacrolimus) et les gouttelettes de l’émulsion (calcitriol). Cette étude est un premier pas vers l’utilisation de ces émulsions pour la co-encapsulation de deux SA dans la même formulation : une première dans les NPs et une seconde dans les gouttelettes d’huile. La co-encapsulation devrait permettre d’améliorer l’observance du patient et pourrait conduire à un effet synergique entre les deux SA. / In this thesis work, we formulated stable, biodegradable and biocompatible Pickering emulsions stabilized with nanoparticles (NPs) of poly(lactic-co-glycolic acid) (PLGA). Such emulsions are an alternative, potentially less toxic and irritating, to conventional emulsions stabilized with surfactants. Firstly, a thorough physico-chemical study of these systems was conducted in order to clarify their structures (macroscopic, microscopic and interfacial) as well as their mechanisms and kinetics of stabilization. Studies of the contribution of the polymer stabilizing the NPs and of the characteristics of the PLGA polymer on the properties of the emulsions were also carried out. This enabled a better identification of the physico-chemical key parameters responsible for a good stabilization. Secondly, we focused on the pharmaceutical potential of these emulsions for a topical application. Pharmaceutical active ingredients (API), used for the treatment of psoriasis, were successfully encapsulated in the NPs (cyclosporine A and tacrolimus) and the emulsion droplets (calcitriol). This study is a first step towards the use of these emulsions for the co-encapsulation of two API: one in the NPs and a second in the oil droplets. The co-encapsulation should improve patient compliance and could lead to a synergistic effect between the two API.

CHARLES UNIVERSITY Faculty of Pharmacy in Hradec Kralove Department of Pharmaceutical Technology Name: Vendula Longinová Title of diploma thesis: Rheological and adhesive properties of matrix for freeze-dryied oral vaccines Supervisor: PharmDr. Eva Snejdrova, Ph.D. The aim of the diploma thesis was to evaluate the rheological and adhesive properties of formulations for lyophilized oral vaccines and lyophilized tablets formulated on the basis of dextran, iota-carrageenan or trehalose. The theoretical part characterizes dosage forms for application to the oral cavity, lyophilized preparations and excipients for mucoadhesive preparations. In the experimental part, rheological and mucoadhesive properties on a rotary rheometer were evaluated. Formulations containing iota-carrageenan showed higher viscosity, higher gel stiffness, lower degree of relaxation and higher yield stress than trehalose formulations. All lyophilized tablets showed sufficient adhesion to a standardized mucin support in vitro. The performed experiments represent pilot tests of flow, viscoelastic and mucoadhesive properties of lyophilized tablets for oral administration of pertussis vaccine. The contribution of the work is the design of a testing methodology for the final formulations during stability tests. Key words: lyophilized...

The main challenge in disease treatment is no more the discovery of new therapeutic drugs, but to provide targeted delivery of therapeutic drugs to specific sites without incurring systemic toxicity effects. An efficient way of reducing the toxicity is by encapsulating the drug with a biodegradable matrix that can provide controlled release of the drug along with local heating of the drug. Local heating can be obtained by incorporating magnetic iron oxide particles that heat upon exposure to AC electromagnetic fields. The magnetic iron oxide nanoparticles are also gaining much attention as MRI contrast agents. Thus it would be of potential benefit if a drug delivery system is designed to encapsulate the drug as well as the magnetic iron oxide nanoparticles within a biodegradable matrix, thereby providing a dual modal imaging and therapeutic delivery system. The key step in the design of a dual modal drug delivery system is the encapsulation of the magnetic iron oxide nanoparticles with polymer of choice. The magnetic iron oxide nanoparticles were encapsulated into a robust poly (styrene-co-vinylbenzylchloride-co-divinylbenzene) (PSVBDVB) to study these synthetic variations upon encapsulation with a polymer. The next step to the design of drug delivery system was to replace the PSVBDVB polymer by a biocompatible and biodegradable polymer- Poly (lactide-co-glycolide) (PLGA). The PLGA composites containing the Fe@FeOx core shell nanoparticles and the drug analog [Ru(bpy) dye] was prepared by oil-in water emulsion solvent evaporation technique. The local heating of the PLGA composites was also achieved by irradiating the Fe@FeOx nanoparticles with 2.45 GHz microwave radiations. Higher Ru(bpy) dye release from the composites by locally heating the sample with 2.45 GHz microwave pulse compared to externally heating the composite sample was achieved. The final step was the design of controlled release drug delivery system with dual modal imaging and therapeutic capabilities. To obtain narrow sized PLGA composites the Fe@FeOx nanoparticles were replaced by chloroform based ferrofluid. The ferrofluid was synthesized by novel thermolysis technique. The release of the dye from the PLGA composites when placed in the Rf induction coil was determined by fluorescence spectroscopy and a linear increase in the fluorescent intensity was observed with time. Also, the controlled release of the dye from the composites was achieved by a pulsed Rf treatment. Magnetic resonance imaging was also performed using the PLGA composites which showed enhancement in the T2-weighted image contrast and thus negligible reduction in the contrast capabilities of the iron oxide particles (R2 = 58.7 s-1mM-1). The PLGA composites containing the drug analog and the iron oxide nanoparticles thus constitute a controlled release drug delivery system with dual modal imaging and therapeutic capabilities.

Tissue engineering offers a potential alternative therapy to overcome the limitations of organ transplantation, by employing biomaterials as scaffold for cell growth. For example, poly-lactic-co-glycolic acid (PLGA) is a synthetic biomaterial widely used in tissue engineering. However, the hydrophobicity of PLGA results in scaffolds that are poorly wettable, and which, therefore, possess poor mass transfer properties for the delivery of nutrients and the removal of waste. The present work aimed to develop more hydrophilic PLGA scaffolds, specifically hollow fibre membranes, within a bioreactor system, which enables co-culture of cells in order to direct stem cell differentiation. Large quantities of costly growth factors are required over long periods for stem cell differentiation. Therefore, this project also aimed to use a cell line as a “factory” for the inexpensive, in situ growth factor production. Hollow fibres were fabricated by wet spinning and a hydrophilic polymer, polyvinyl alcohol (PVA), was added to the PLGA solution at three different concentrations (1.25, 2.5, 5% w/w) in order to obtain a more hydrophilic membrane. Results indicated that 5% PVA-PLGA hollow fibres were the only membranes which allowed permeation of water, BSA and cell-secreted hepatocyte growth factor (HGF), thus indicating that they are the most suitable membranes for use in bioreactor devices. However, these membranes failed to improve cell-attachment. Cell secreted HGF was shown to be more stable in a dynamic culture environment than commercial HGF, thus suggesting its suitability for applications in bioreactor devices. However, using both commercial and cell-secreted HGF, mesenchymal stem cell differentiation was unsuccessful. In conclusion, this work has developed a hollow fibre membrane which is more permeable to water and proteins for a higher mass transfer of nutrients, and has realised a model system for the inexpensive production of growth factors for use in bioreactor devices and the differentiation of stem cells.

Injuries to the central nervous system (CNS) have traumatic consequences such as irreparable disability due to the inability of the CNS to regenerate injured nerve fibres. The aim of the work presented here was to develop a scaffold which potentially provides guidance to axons in the injured spinal cord thus facilitating signal transduction. A poly-(lactic-co-glycolic acid) (PLGA, PLA:PGA ratio of 75:25) flat sheet membrane scaffold was created using phase inversion with N-methyl pyrrolidinone (NMP) as the solvent and water as the non-solvent for immersion precipitation. PLGA flat sheet membranes were exposed to surface treatments including aminolysis, peptide immobilisation and ozonation in order to achieve higher cell attachment of PC12 cells, a cell line which was cloned from a solid pheochromocytoma tumour of white rats, and used as a tool for measurement of regeneration. Cell attachment studies revealed no significant difference in cell attachment between modified and not-modified PLGA flat sheet membranes. However, the absence of foetal calf serum (FCS) resulted in fivefold higher cell attachment compared to medium supplemented with 10% FCS. A second scaffold was produced by electrospinning 10% (w/w) PLGA in a chloroform:methanol (CHCl3:MeOH) mixture in ratio of 3:1 resulting in a nanofibrous scaffold. Optimum settings for electrospinning were found to be 3 ml/h feeding rate, 15kV applied voltage and 11cm collector-to-needle distance. Random and aligned PLGA nanofibres were produced, with a fibre diameter of 530±140nm. PC12 cells attached and differentiated to the nanofibrous scaffold. When exposed to NGF these cells stopped dividing and extended neurites. On random fibres, neurite orientation was random, whereas on aligned fibres 63% of neurites grew with the fibre orientation ±15��ᵒ. After 7 days of exposure to NGF, cells had 1-4 neurites on random fibres, reaching a maximum length of 188μm, whereas on aligned fibres, cells had 1-2 neurites, reaching a maximum length of 400μm. PLGA nanofibres were also investigated as a delivery vehicle for bioactive molecules. For this, poly-L-lysine (PLL) was incorporated into electrospun PLGA nanofibres via emulsion electrospinning. PLGA-PLL nanofibres were significantly larger than PLGA nanofibres having a diameter of 830±190nm. In order to visualise the incorporation of PLL, FITC-PLL was electrospun und the resulting nanofibres fluoresced greed. Attachment of PC12s to PLGA-PLL nanofibres was not significantly different compared to PLGA nanofibres. Aligned PLGA-PLL nanofibres were shown to promote neurite outgrowth of PC12s with resulting neurites of up to twice the length compared to aligned PLGA nanofibres. The results suggest that PLGA nanofibres strongly influences neurite organisation, which is potentially useful for future therapeutic approaches. The work in this thesis has shown that electrospun PLGA nanofibre mats have the potential to be used as scaffolds for spinal cord repair addressing topographical guidance and delivery of bioactive molecules to the site of injury.