Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-08-07T13:57:03Z No. of bitstreams: 0 / Made available in DSpace on 2015-08-07T13:57:04Z (GMT). No. of bitstreams: 0 / O interesse crescente no desenvolvimento de biomateriais com superfície porosa para aplicações dentárias decorre do suporte propicio ao crescimento do tecido ósseo, aumentando a adesão entre o tecido e material, favorecendo a osteointegração. O titânio pode ser considerado um ótimo material para implantes dentários, pela sua excelente biocompatibilidade, elevada resistência à corrosão e combinação de alta resistência com baixa densidade. Contudo, a alta reatividade do metal no estado líquido acaba dificultando a fabricação de implantes por fundição, sendo a metalurgia do pó composta por técnicas que permitem a obtenção de peças em temperaturas menores de processamento (estado sólido) e com módulo elástico próximo ao do tecido ósseo. O objetivo deste trabalho foi avaliar amostras porosas obtidas pela Metalurgia do Pó (MP) convencional. Inicialmente o pó de titânio comercialmente puro (Ti-cp) obtido pelo processo de hidretação-dehidretação (HDH), foi compactado em matriz uniaxial e sinterizado a vácuo em duas temperaturas,1100 e 1150°C/1h. As amostras sinterizadas foram caracterizadas quanto à densidade, porosidade, microestrutura ( microscopia óptica - MO e microscopia eletrônica de varredura - MEV), fases cristalinas (difração de raios - X - DRX), propriedades mecânicas (microdureza e ensaio de flexão em três pontos), comportamento eletroquímico (potencial de circuito aberto, espectroscopia de impedância eletroquímica e polarização anódica) e o ensaio de imersão foram empregados nas amostras obtidas por (MP) e no titânio fundido. Os resultados indicaram morfologia angular, distribuição granulométrica com média de 45 μm, além de densidade aparente e escoabilidade baixas. Foram obtidas amostras com porosidade de aproximadamente 33% e poros interligados dentro de uma faixa de tamanho de 110 140 μm. As análises por MEV e DRX das amostras sinterizadas indicaram a presença de fase α e poros. As amostras sinterizadas a 1150°C revelaram melhor comportamento mecânico em relação as amsotras sinterizadas a 1100°C. As análises eletroquímicas indicaram a elevada resistência a corrosão do titânio fundido, seguida pela amostra sinterizada 1100°C e finalmente das sinterizadas a 1150°C, quando imersas em solução da saliva artificial. O EDS foi executado para verificar a deposição de elementos na superfície. Testes de citotoxicidade demonstraram que o pó e as amostras sinterizadas não apresentaram qualquer efeito tóxico em culturas celulares. As amostras sinterizadas à 1100°C possuiam grau de porosidade e tamanho de poros que favoreceram o crescimento do tecido ósseo, além do módulo de elasticidade próximo ao tecido ósseo e foram mais resistentes a corrosão na solução simuladora. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Orientadores: Giselle Maria Marchi, Carlos Alberto de Souza Costa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-13T06:19:18Z (GMT). No. of bitstreams: 1 Lima_AdrianoFonsecade_M.pdf: 16947758 bytes, checksum: c368a477af40a0e63ffe78a57bea6537 (MD5) Previous issue date: 2009 / Resumo: Os objetivos do presente trabalho foram: a) avaliar os efeitos citotóxicos diretos e transdentinário de diferentes concentrações de peróxido de carbamida (PC) sobre as células de linhagem odontoblástica MDPC-23; b) avaliar o efeito protetor (antioxidante) do ascorbato de sódio (AS) sobre estas células expostas a agentes clareadores, na forma direta e transdentinária; c) avaliar o montante de peróxido de hidrogênio (H2O2) liberado por agentes clareadores a base de PC 10% e 16% que se difunde através de discos de dentina com 0,5mm de espessura. No Experimento 1, células odontoblásticas foram cultivadas em wells e incubadas por 48 horas. O gel clareador foi solubilizado em meio de cultura (DMEM) originando diferentes extratos, e a quantidade (µg/mL) de H2O2 liberado em cada extrato foi mensurada através da técnica de leucocristais violeta/enzima horseradish peroxidase (LCV/HRP). Os seguintes grupos foram estabelecidos (n=10): G1-DMEM sem gel clareador (controle); G2-0,0001% PC (0,025µg/ml de H2O2); G3-0,001% PC (0,43µg/ml de H2O2); G4-0,01% PC (2,21µg/ml de H2O2); e G5-0,1% PC (29.74µg/ml de H2O2). As células foram expostas por 60 minutos aos diferentes extratos, e então realizada a análise da viabilidade celular (Teste de MTT). Somente os grupos 2 e 3 não apresentaram diferença estatística quando comparados ao controle (G1) (p>0,05). Os maiores efeitos citotóxicos foram observados para G4 e G5, sendo que G5 foi estatisticamente diferente que G4, apresentando-se mais tóxico às células. No experimento 2, células MDPC-23 foram cultivadas e incubadas por 48h. O PC e o AS foram solubilizados em meio de cultura (DMEM), para obtenção dos extratos experimentais. Os seguintes grupos foram estabelecidos: G1-DMEM sem gel clareador (controle); G2- 0,25mM de AS; G3-0,5mM de AS; G4-0,25mM de AS + 0,01% de PC; e G5-0,5mM de AS + 0,01% PC e G6-0,01% de PC. As células foram expostas por 60 minutos aos diferentes extratos, e depois foi realizado o teste de MTT. O grupo 6 apresentou a maior citotoxicidade quando comparado com os demais grupos, enquanto que o AS produziu uma diminuição dos efeitos citotóxicos do agente clareador, demonstrando uma proteção frente aos componentes deste produto. No Experimento 3, discos de dentina (0,5mm de espessura) obtidos de terceiros molares humanos foram fixados em uma câmara pulpar artificial (CPA). As células odontoblásticas foram semeadas na superfície pulpar dos discos, e os seguintes grupos foram estabelecidos: Grupo 1 - Sem tratamento (Controle); Grupo 2 - Antioxidante 10% (AS)/6h; Grupo 3- Peróxido de Carbamida (PC) 10% /6h; Grupo 4- AS10%/6h+PC10%/6h; Grupo 5- PC16% /6h; Grupo 6- AS10%/6h+PC16%/6hs. Após os tratamentos, foi realizado o teste de MTT. A difusão de H2O2 somente para os grupos 3 e 5 foi mensurada através da técnica de LCV/HRP. Todos os grupos foram estatisticamente semelhantes, exceto o G6. O PC 16% apresentou a maior difusão transdentinária. Pode-se concluir que o PC apresenta efeitos citopáticos para as células odontoblásticas MDPC-23, na forma direta ou transdentinária e que esta citotoxicidade é dose-dependente. O ascorbato de sódio possui a capacidade de reduzir os efeitos citotóxicos do peróxido de carbamida, sobre estas mesmas células em cultura. / Abstract: The aims of this present study were: a) to evaluate the direct and transdentinal cytotoxic effects of carbamide peroxide (CP) bleaching gel at different concentrations on odontoblast-like cells MDPC-23; b) to evaluate the protective effect (antioxidizing) of sodium ascorbate (SA) on these cells expose to bleaching agents, on direct and transdentinal mode; c) to evaluate the amount of hydrogen peroxide (H2O2) released by bleaching agents based to CP 10% and 16%, that diffuses through dentin discs with 0.5mm thickness. In Experiment 1, odontoblastic cells were seeded in wells and incubated for 48 hours. The bleaching gel was diluted in DMEM culture medium originating different extracts, and the amount (µg/mL) of H2O2 released from each extract was measured by the leukocrystal violet/horseradish peroxidase enzyme (LCV/HRP) assay. The following groups were established (n=10): G1-DMEM without bleaching gel (control); G2-0.0001% CP (0.025 µg/mL H2O2); G3-0.001% CP (0.43 µg/mL H2O2); G4-0.01% CP (2.21 µg/mL H2O2); and G5-0.1% CP (29.74 µg/mL H2O2). MDPC-23 cells were exposed to the bleaching gel extracts for 60 minutes and then performed the cell viability analysis (MTT assay). Only G2 and G3 were not significantly different from control group (G1) (p>0.05). The most severe cytotoxic effects were observed in G4 and G5, and G5 was statistically different to G4, presenting more toxic to the cells. In Experiment 2, MDPC-23 cells were seeded in wells and incubated for 48 hours. CP and SA were dissolved in culture medium (DMEM) in order to obtain the experimental extracts. The following groups were established: G1-no treatment (control); G2-0,25mM SA; G3-0,5mM SA; G4-0,25mM SA + 0,01% CP; e G5-0,5mM SA + 0,01% CP e G6-0,01% CP. The cells were expose to different extracts for 60 min, and then was performed the MTT assay and. Group 6 presented higher cytotoxicity than the other groups, while the SA decreased the cytotoxic effects caused by CP, demonstrating its protective effect against the toxic components of this dental product. In Experiment 3, dentin discs (0.5mm thick) obtained from human third molars were fixed in an artificial pulp chamber (APC). The odontoblastic cells were seeded on pulp surface of the discs, and the following groups were established: Group 1 - No treatment (Control); Group 2 - Antioxidizing 10% (SA)/6h; Group 3- Carbamide Peroxide (CP) 10%/6h; Group 4- SA10%/6h+CP10%/6h; Group 5- CP16%/6h; Group 6- SA10%/6h+CP16%/6hs. After the treatments, MTT assay was performed. The H2O2 diffusion only to the groups 3 and 5 was measured by the LCV/HRP assay. All groups were statistically similar, except G6. The CP 16% presented the higher transdentinal diffusion. It can be conclude that CP presents citotoxic effects to the odontoblastic-like cells MDPC-23, in direct and transdentinal mode and this citotoxicity is dose-dependent. The sodium ascorbate was able to reduce the cytotoxic effects the concentration of 0.1% of PC caused the most intense cytopathic effects of carbamide peroxide on the same cells in culture. / Mestrado / Dentística / Mestre em Clínica Odontológica

Orientadores: Cássio Luís Zanettini Riccetto, Benedicto de Campos Vidal / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-21T17:40:56Z (GMT). No. of bitstreams: 1 Siniscalchi_RodrigoTeixeira_D.pdf: 4712721 bytes, checksum: 84737665d5451453e82931eab2e748c4 (MD5) Previous issue date: 2012 / Resumo: Introdução: O material sintético (tela) mais utilizado atualmente no tratamento da Incontinência Urinária de Esforço (IUE) e dos prolapsos da parede vaginal, também conhecidos como Prolapsos dos Orgãos Pélvicos (POP) é o polipropileno monofilamentar, com índices de cura de até 90%. Porém, as complicações relacionadas à integração tecidual desses implantes são relativamente prevalentes. O colágeno, por ser um material biologicamente compatível, pouco imunogênico e com propriedades moduladoras do processo inflamatório, pode ser utilizado como um importante agente cicatrizante e, nesse sentido, poderia melhorar a integração das telas. Objetivo: Estudar os efeitos biomecânicos e histológicos do recobrimento de tela de polipropileno monofilamentar com gel purificado de colágeno, implantadas no tecido subcutâneo de ratas. Material e Métodos: Vinte ratas foram utilizadas para o estudo histológico e outras 20 para o estudo biomecânico. De um lado da parede abdominal do animal foi implantado um fragmento tela de polipropileno monofilamentar macroporosa medindo 20 x 10 mm, habitualmente utilizada no tratamento da IUE e dos POP (Grupo I), denominada PLP (tela de polipropileno) e do outro lado foi implantada uma tela com as mesmas dimensões recoberta com gel purificado de colágeno (Grupo II), denominada PLP+C (tela de polipropileno recoberta com o gel purificado de colágeno). De acordo com o tempo de eutanásia (7, 30, 90 ou 180 dias) após o implante os animais de cada grupo foram divididos em quatro subgrupos contendo cinco animais cada. Foi então realizada excisão em bloco da parede abdominal para as análises. O estudo biomecânico foi realizado em um tensiômetro de precisão, no qual a tela era tracionada em sentido uniaxial até que se desprendesse da interface tecidual. Para quantificar a aderência do material, em cada grupo, foi analisada a carga máxima necessária para este desprendimento. No estudo histológico foram analisadas as características relativas à inflamação aguda e crônica além do tecido de granulação, formação de granuloma e reação de corpo estranho em lâminas coradas com Hematoxilina-Eosina (HE), utilizando-se de método semiquantitativo. A organização supramolecular da deposição colágena em torno das telas foi estudada através de microscopia de polarização (birrefringência). Resultados: No estudo biomecânico observou-se que a aderência das telas de polipropileno aos tecidos circunvizinhos aumentou significativamente após o recobrimento com o gel purificado de colágeno, como demonstrado na análise dos valores encontrados para a Carga Máxima no 7º (p=0,0016), 14º (p=0,0039), 90º (p=0,0009) e 180º (p=0,0029) dias após o implante. Considerou-se nessa pesquisa, que o aumento da biocompatibilidade da tela de polipropileno seria alcançado quando, na interface tecidual, houvesse redução da intensidade do processo inflamatório. Verificou-se que a resposta inflamatória crônica e aguda (neutrofílica), assim como a formação de tecido de granulação foi menos intensa, respectivamente p=0,004, p<0,001 e p=0,001 nas telas recobertas com o colágeno na fase inicial (7º e 14º dias) e ausente, assim como nas telas não recobertas na fase tardia (90º e 180º dias). A inflamação granulomatosa foi observada de forma menos significativa aos sete dias após o implante nos animais do grupo II (p=0,029) e em ambos os grupos, de maneira similar, diminuiu ao longo do tempo não mostrando diferença significativa. A reação de corpo estranho foi menos intensa na fase inicial no grupo II (p<0,001) e semelhante entre os grupos na fase tardia. Nas análises de birrefringência foi observado no período inicial (sete dias) uma maior densidade média de brilho (transmitância) a favor das telas não recobertas (p=0,000), porém nos outros períodos analisados a densidade média de brilho foi maior nas tela do grupo II (PLP+C), 14 dias (p=0,000), 90 dias (p=0,000) e em 180 dias (p=0,000). Conclusão: O recobrimento das telas de polipropileno com o gel purificado de colágeno aumentou sua aderência aos tecidos, quando implantadas na interface da parede abdominal de ratas adultas, tanto precocemente quanto tardiamente; promoveu uma resposta inflamatória menos intensa e duradoura e na fase tardia do implante desencadeou maior organização e empacotamento das fibras de colágeno. Estes dados inferem que a tela recoberta com o gel purificado de colágeno quando locada em seu leito de implante terá, provavelmente, menor mobilidade e também uma melhor adaptação e integração ao corpo do hospedeiro resultando em menor chance de complicações / Abstract: Introduction: The synthetic material most currently used in the treatment of stress urinary incontinence (SUI) and vaginal wall prolapse, also known as pelvic organ prolapse (POP) is the monofilament polypropylene mesh (PLP). However, complications related to tissue integration of these implants are relatively prevalent. Collagen is the main structural protein of mammals, which modulates inflammatory process, and can be used as an important healing agent and, accordingly, could improve the integration of the meshes. Objetives: To study the biomechanical and histological effects of PLP, coated with purified collagen gel, implanted in the subcutaneous tissue of adult rats. Methods: Twenty rats were used for histological study and other 20 for the biomechanical study. At one side of the abdominal wall, PLP fragment measuring 20x10 mm was implanted (Group I), and in the other side a mesh fragment with the same dimensions coated with purified collagen gel PLP+C) was implanted (Group II). According to the time of euthanasia (7, 30, 90 or 180 days) after implantation the animals from each group were divided into four subgroups of five animals each. The biomechanical study was performed with a precision tension meter with in bloc fresh abdominal wall sample containing the mesh. The mesh was pulled up in uniaxial direction until complete detachment of the tissue interface and the maximum load required for the detachment was analyzed in each group. In the histological study, it was examined characteristics of the acute and chronic inflammatory reaction, granulation tissue, granuloma formation, and foreign body reaction on slides stained with hematoxylin-eosin. The supramolecular organization of the collagen deposition around the meshes was studied with polarizing microscopy (birefringence analysis). Results: In biomechanical study it was observed that the adhesion of PLP to surrounding tissues increased significantly after coating with purified collagen gel, as shown in the analysis of the maximum load at the 7th (p=0.0016), 14th (p=0.0039), 90th (p=0.0009) and 180th (p=0.0029) days after implantation. It was considered in this research, that increased biocompatibility of PLP would be achieved when, in tissue interface, there was a reduction of the intensity of the inflammatory process. It was found that the acute and chronic inflammatory response, as well as the formation of granulation tissue were less intense, respectively p=0.004, p<0.001 and p=0.001 for PLP+C in the initial phase (7th and 14th days) and missing, as well as on the meshes not covered in late phase (90th and 180th days). Granulomatous inflammation was less significant seven days after implantation in animals of Group II (p=0.029) and in both groups, similarly, decreased over time showing no significant difference. The foreign body reaction was less intense in the initial phase in Group II (p<0.001) and similar between the groups in the late phase. In the birefringence analyses, it was noted a greater average density of brightness (transmittance) in PLP (p=0.000) in the initial period (seven days), but in other periods it was greater for PLP+C [14 days (p=0.000); 90 days (p=0.000) and 180 days (p=0.000)]. Conclusions: Coating of polypropylene meshes with purified collagen gel increased their adhesion to the tissues, when implanted in the subcutaneous of the abdominal wall of adult rats and promoted a less intense and lasting inflammatory response and, in the late stage of the implant, triggered greater organization and packaging of collagen fibers. Based on that, one can suppose that mesh coated with purified collagen gel can fix better to the host tissues preventing its displacing, and can elicit fewer integration defects, resulting in less chance of complications / Doutorado / Fisiopatologia Cirúrgica / Doutor em Ciências

A huge discrepancy between the number of patients on the waiting list for organ transplants and the actual available donors has led to search for alternative approaches to substitute compromised or missing tissues and organs. Tissue engineering is a promising alternative to organ transplantation with the aim to fabricate functional organs through the use of biological or biocompatible scaffolds. Nanogels made from self-assembling ultrashort peptides are promising biomaterials for a variety of biomedical applications. Our group at KAUST is interested in the development of novel synthetic peptide-based biomaterials that combine the advantages of both natural and synthetic hydrogels for various applications. In this study, we have investigated two compounds of a novel class of rationally designed ultrashort peptides, Ac-IVFK-NH2 (Ac-Ile-Val-Phe-Lys-NH2) and Ac-IVZK-NH2 (Ac-Ile-Val-Cha-Lys-NH2). These compounds have an innate tendency to self-assemble into nanofibrous hydrogels which can be used as 3D scaffolds, for example for the fabrication of 3D skin grafts for wound healing. We have evaluated the efficacy of the peptide scaffolds in treating full-thickness wounds in minipigs. Additionally, we assessed the ability of these scaffolds in supporting skeletal muscle tissue proliferation and differentiation. We found that our innovative nanogels supported a substantial increase in human dermal fibroblast and myoblast growth and cells viability, and supported myoblast differentiation. Also, microscopic observation of the direct contact of keratinocytes and fibroblasts revealed enhancement in keratinocytes proliferation. In addition, we demonstrated the ability of human umbilical vein endothelial cells to form tube like structure within peptide nanogels using immunofluorescence staining. Moreover, we successfully produced artificial 3D vascularized skin substitutes using these peptide scaffolds. We selected these peptide nanogels and were able to produce in situ silver nanoparticles within the nanogels, solely through UV irradiation, with no reducing agent present. We then assessed the efficacy of the silver nanoparticle-containing peptide nanogels on minipigs with full-thickness excision wounds. The application of the peptide nanogels on full thickness minipig wounds demonstrated that the scaffolds were biocompatible and did not trigger wound inflammation, and thus safe for topical application. The effect of nanogels, both with and without the addition of the silver nanoparticles, revealed that the scaffold itself has a high potential to act as an antibacterial agent. Interestingly, the effect of the peptide nanogels on wound closure was comparable to that of standard care hydrogels. Furthermore, we have demonstrated that both peptides can act as printable bioinks which opens up the possibility of 3D bioprinting of different cell types in the future. We believe that the described results represent an advancement in the context of engineering skin and skeletal muscle tissue, thereby providing the opportunity to rebuild missing, failing, or damaged parts.

Polyetheretherketone (PEEK) is a Federal and Drug Administration (FDA) approved biomaterial that has been used as an orthopedic implant material due to its inherent properties. Laser etching has become a popular means to create identication markers on the individual implants as required by the FDA. The interaction of laser energy with polymeric materials could potentially cause changes in the material's biocompatibility and mechanical properties. The objective of this study was to determine the effect of laser energy on the biocompatibility and mechanical properties of implantable PEEK by measuring contact angle, micro-tensile testing, nite-element modeling (FEM), and biocompatibility testing according to International Organization for Standardization (ISO) 10993 for cytotoxicity. The results of the study showed that the etching characteristics were mostly in by the laser power and the laser pulse spacing. The mechanical properties were degraded by the laser and the tensile strength of the material was decreased by 50% is some cases. The laser, however, did not affect the biocompatibility. The biocompatibility testing of the material showed no cytotoxic effect using an agar overlay method. The contact angle measurements demonstrated that the laser etching produced a hydrophobic effect to the surface. The FEM model demonstrated a good correlation between the laser power and the vaporization of the PEEK material. The results of the study showed the effect of laser energy on biocompatibility and mechanical properties.

Due to its strength, flexibility, and biocompatibility, spider silk is a highly appealing material for applications in the medical field. Unfortunately, natural spider silk is difficult to obtain in large quantities because spiders are territorial and cannibalistic, making them impractical to farm. Synthetic spider silk proteins produced by transgenic hosts such as bacteria and goats have made it possible to obtain the quantities of spider silk needed to study it more fully and to investigate its potential uses. The spider silk proteins produced in our laboratory do not have an optimal purification method to remove all of the non-biocompatible contaminants and have not previously been tested for their biocompatibility. The first focus of this dissertation was to create goat cells that can be used to create new goats. These new goats will produce proteins that can be purified more efficiently and more completely. The second focus of this dissertation was to perform biocompatibility tests on goat-derived spider silk proteins. Prior to performing any biocompatibility tests, a method was established for removing endotoxins – an impurity that causes an immune response in the body – from the proteins. This work has shed light on areas for improvement in the silk protein purification process and laid groundwork for the production of new goat-derived proteins. These steps will help make it possible for synthetic spider silk to progress further toward becoming a viable biomaterial.

The Tissue Engineering Research Lab at California Polytechnic State University, San Luis Obispo focuses on creating tissue-engineered blood vessel mimics (BVMs) for use in preclinical testing of vascular devices. These BVMs are composed of electrospun scaffolds made of an assortment of polymers that are seeded with different cell types. This integration of polymers with cells leads to the need for biocompatibility testing of the polymer scaffolds. Many of the lab’s newest scaffolds have not been fully characterized for biologic interactions. Therefore, the first aim of this thesis developed methods for in vitro cytotoxicity testing of polymers used in the fabrication of BVMs. This included cytotoxicity testing using direct contact and elution-based methods, along with fluorescent staining to visualize the scaffold effects on cells. The second aim of this thesis implemented the newly developed cytotoxicity protocols to evaluate the biocompatibility of existing polymers, ePTFE and PLGA, used in the tissue engineering lab. The results demonstrated that ePTFE and PLGA were noncytotoxic to cells. The third aim of this thesis evaluated the biocompatibility of novel polymers used to fabricate BVMs: PLGA with salt, PLLA, and PCL. Elution-based methods concluded that PLGA with salt, PLLA, and PCL were noncytotoxic to cells; however, the direct contact method illustrated PLGA with salt and PCL were mildly cytotoxic at 24 and 48 hours. Potential causes of this variability include the addition of salt to PLGA, dissolving PCL in dichloromethane, inadequate sample sizing, and the inherent differences between the test methods. Overall, this thesis developed and implemented methods to evaluate the biocompatibility of polymer scaffolds used in the BVM model, and found that ePTFE, PLGA, and PLLA scaffold materials were biocompatible and could be implemented in future BVM setups without concerns. Meanwhile, PLGA with salt and PCL’s toxicity was mild enough to urge future cytotoxicity testing on PLGA with salt and PCL before further use in the lab.

No description available.

No description available.

After skeletal muscle damage, satellite cells move towards the injured area to assist in regeneration. However, these cells are rare as their numbers depend on the age and composition of the injured muscle. This regeneration method often results in scar tissue formation along with loss of function. Although several treatment methods have been investigated, no muscle replacement treatment currently exists. Tissue engineering attempts to create, repair, and/or replace damaged tissue by combining cells, biomaterials, and tissue-inducing substances such as growth factors. Electrospinning produces a non-woven scaffold out of biomaterials with fiber diameters ranging from nanometers to microns to create an extracellular-like matrix on which cells attach and proliferate. Our focus is on synthetic polymers, specifically poly(D,L-lactide) (PDLA), poly(L-lactide) (PLLA), and poly(ε-caprolactone) (PCL). Skeletal muscle cells grown on electrospun scaffolds tend to elongate and fuse together thus, mimicking natural tissue. Electrical stimulation has been shown to increase the number of cells fused in culture and decreased the time needed in culture for cells to contract. Therefore, a conductive element was added to each scaffold, specifically polyaniline (PANi), gold nanoparticles (Au Nps), and multi-walled carbon nanotubes (MWCNT). Our project goal is to create a polymeric, conductive, and biocompatible scaffold for skeletal muscle regeneration. PANi and PDLA were mixed to form the following solutions 24% (83% PDLA/17% PANi), 24% (80% PDLA/20% PANi), 22% (75%PDLA/25% PANi), 29% (83% PDLA/17% PANi), and 29% (80% PDLA/20% PANi). Only the 75/25 electrospun scaffold was conductive and had a calculated conductivity of 0.0437 S/cm. Scaffolds with larger amounts of PANi were unable to be electrospun. PDLA/PANi scaffolds were biocompatible as primary rat skeletal muscle cells cultured in vitro did attach. However, the scaffolds shrunk, degraded easily, and became brittle. Although PDLA/PANi scaffolds were easily manufactured, our results indicate that this polymer mixture is not appropriate for skeletal muscle scaffolds. PLLA and Au Nps were electrospun together to form three composite scaffolds: 7% Au-PLLA, 13% Au-PLLA, and 21% Au-PLLA. These were compared to PLLA electrospun scaffolds. Measured scaffold conductivities were 0.008 ± 0.015 S/cm for PLLA, 0.053 ± 0.015 S/cm for 7% Au-PLLA, 0.076 ± 0.004 S/cm for 13% Au-PLLA, and 0.094 ± 0.037 S/cm for 21% Au-PLLA. It was determined via SEM with a Bruker energy dispersive x-ray spectrometer (EDS) that the Au Nps were not evenly distributed within the scaffolds as they had agglomerated. Rat primary muscle cells cultured on the three Au-PLLA scaffolds displayed low cellular activity. A second cell study was conducted to determine Au NPs toxicity. The results show that the Au Nps were not toxic to the cells and the low cellular activity may be a marker for myotube fusion. Elastic modulus and yield stress values for the three Au-PLLA scaffolds measured on days 0, 7, 14, 21, and 28 were much larger than skeletal muscle tissue. Due to the larger mechanical properties and Au Nps agglomeration, a third polymer and conductive element scaffold was investigated. PCL was chosen as the new synthetic polymer as it had a lower elastic modulus and high elongation. MWCNT were chosen as the conductive element as they disperse well within PCL when acid functionalized. A third component was added to the scaffold to help it move similar to skeletal muscle. Ionic polymer gels (IPG) are hydrogels that respond to an external stimulus such as temperature, pH, light, and electric field. A poly(acrylic acid)/poly(vinyl alcohol) (PAA/PVA) mixture is one type of IGP that responds to an electric field. The scaffolds were coaxially electrospun so that each fiber had a PCL-MWCNT interior with a PAA/PVA sheath. These scaffolds were compared to electrospun PCL and PCL-MWCNT ones. The addition of MWCNT to the PCL did increase scaffold conductivity. Actuation of the PCL-MWCNT-PAA/PVA scaffold occurred when 15V and 20V were applied. All three scaffolds had rat primary skeletal muscle cells attached but, more multinucleated cells with actin interaction were seen on PCL-MWCNT-PAA/PVA scaffolds. Once again the mechanical properties were greater than muscle, but because of its ability to actuate we believe the PCL-MWCNT-PAA/PVA scaffold has potential as a bioartificial muscle. Further characterization of the PCL-MWCNT-PAA/PVA included varying the ratios of PAA/PVA, smaller crosslinking times, and lower amounts of MWCNT. Four ratios, 83/17, 60/40, 50/50, and 40/60, were successfully coaxially electrospun with PCL and MWCNT. Overall, very few differences were seen between the four ratios in conductivity, cellular biocompatibility, actuation angular speed, and mechanical properties. The 83/17 and 40/60 ratios were chosen for additional investigation into mechanical properties and actuation. As the mechanical properties of the two types of scaffolds did not change significantly through degradation, lower PVA crosslinking times were tested. No significant effects were found and it was hypothesized that the evaporation of the solution played a role in the crosslinking process. The smaller MWCNT amount scaffolds also did not significantly affect the mechanical properties or the actuation angular speeds. More work into lowering the scaffold mechanical properties while increasing the actuation angular speed is necessary. Though the mechanical properties for the 83/17 and 40/60 scaffolds remained high compared to skeletal muscle, we also looked for differences in in vivo biocompatibility. Both scaffolds were implanted into the right vastus lateralis muscle of Sprague-Dawley rats. The left vastus lateralis muscle served as either the PBS injected sham surgery or an unoperated control. Biocompatibility was evaluated using enzymes, creatine kinase (CK) and lactate dehydrogenase (LDH), levels, fibrosis formation, inflammation, scaffold cellular infiltration, and neovascularization on days 7, 14, 21, and 28 post-implantation. Fibrotic tissue formation, inflammation, and elevated CK and LDH levels were observed initially but responses decreased during the four week study. Cells infiltrated the scaffolds and histological staining showed more fibroblasts than myogenic cells initially but over time, the fibroblasts decreased and myogenic cells increased. Neovascularization of both scaffolds was also recorded. PCL-MWCNT-PAA/PVA scaffolds were determined to be biocompatible, but some differences between the two types were noted. The 83/17 scaffolds caused less of a response from the body compared to the 40/60 scaffolds and had more myogenic cells attached. However, the 40/60 scaffolds had a larger number of blood vessels running through the scaffold. In conclusion, we have successfully fabricated a polymeric, conductive, and biocompatible scaffold that can actuate for skeletal muscle tissue engineering. Although our results are promising, more work is necessary to continue developing and refining the scaffold. / Ph. D.