Navegando por Palavras-chave "Scaffold"

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    Análise de diferentes biomateriais como suporte para cultivo de células neurais e células-tronco
    (Universidade Federal de São Paulo (UNIFESP), 2018-05-24) Granato, Alessandro Eustaquio Campos [UNIFESP]; Porcionatto, Marimelia [UNIFESP]; http://lattes.cnpq.br/6155537170968904; http://lattes.cnpq.br/1158085171478998; Universidade Federal de São Paulo (UNIFESP)
    Na primeira parte deste trabalho, apresentamos uma metodologia para a produção e aplicação de materiais híbridos contendo poliéster comercial (poli-butileno adipato-co-tereftalato, PBAT) e um polímero condutor (polipirrole, PPy) produzidos pela técnica de eletrospinning, como arcabouço (scaffold) para cultura e diferenciação de neurônios. As propriedades físico-químicas dos substratos e a otimização dos parâmetros de eletrospinning são apresentados. Os scaffolds eletrofiados são biocompativeis e permitem a aderência e proliferação de células-tronco mesenquimais (CTM). As fibras de PBAT com ou sem PPy foram utilizadas como substrato para adesão e diferenciação de células de neuroblastoma (Neuro2a) de camundongo. As Neuro2a aderiram nos scaffolds de PBAT e PBAT / PPy2% sem revestimento de laminina. No entanto, células Neuro2a estimuladas por ácido retinóico (RA), não diferenciaram quando foram cultivadas em PBAT, mas diferenciaram quando cultivadas em fibras de PBAT / PPy2%. Nossa hipótese é que a hidrofobicidade do PBAT tenha inibido a diferenciação, e que a inibição tenha sido superada ao revestir as fibras de PBAT com laminina. Concluímos que as fibras produzidas com a combinação de PBAT e PPy são um bom suporte para a diferenciação neuronal. Na segunda parte deste trabalho, estudamos scaffolds biológicos descelularizados derivados de cérebros murinos como suporte para cultivo de células neurais. Scaffolds compostos de matriz extracelular (MEC) estão sendo investigados por sua capacidade de facilitar a remodelação e reparo do tecido cerebral após uma lesão. A MEC é um material complexo composto por proteínas, glicoproteínas e proteoglicanos, que são secretados pelas células. A MEC contém pistas biológicas importantes que modulam comportamentos celulares, e também serve como um suporte estrutural ao qual as células podem aderir. No entanto, os protocolos descritos atualmente para a descelularização de órgãos, como o cérebro, envolvem o uso de muitos reagentes químicos com muitas etapas que, em última instância, limitam o processo de recelularização. Portanto, descrevemos pela primeira vez um método simples e rápido para a decelularização completa de cérebro murino. Nossos resultados mostram que, em 24h, os cérebros de camundongos foram completamente descelularizados, mas ainda mantiveram vários componentes MEC essenciais para a sobrevivência celular e repovoamento do scaffold. Além disso, observamos que o scaffold descelularizado de cérebro é biocompatível, pois células Neuro2a injetadas no scaffold e mantidas em cultura durante 24 e 72h foram localizadas e identificadas por imuno-histoquímica na sua forma indiferenciada. Concluímos que este novo método para descelularização do cérebro murino é eficiente e os scaffolds podem ser usados como um suporte biocompatível para o repovoamento celular.
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    Avaliação histológica e funcional da ampliação vesical com "scaffold" biológico e sintético com e sem semeadura de células tronco mesenquimais derivadas de tecido adiposo. Estudo experimental em coelhos.
    (Universidade Federal de São Paulo (UNIFESP), 2019-11-26) Franca, Wagner Aparecido [UNIFESP]; Almeida, Fernando Gonçalves de [UNIFESP] ; http://lattes.cnpq.br/6068952355867561; Universidade Federal de São Paulo (UNIFESP)
    Objective: Evaluate the histological and functional parameters of bladder enlargement in rabbits with the use of extracellular matrix scaffold and synthetic polyglycolic acid (PGA) scaffold, with and without fat-derived stem cell seeding. Methods: Experimental study which presents 5 groups of nine rabbits: control, extracellular matrix scaffold bladder enlargement with fat-derived stem cell seeding, extracellular matrix scaffold bladder enlargement without stem cell seeding, scaffold bladder enlargement with polyglycolic acid and stem cell seeding and finally group of scaffold bladder enlargement of polyglycolic acid without stem cell seeding. Bladder function was evaluated by analysis of maximal cystometric capacity and bladder capacity in detrusor pressure of 40 cmH20, by urodynamic study and histology, both on the fourth, eighth and twelfth week. Histological analysis was performed with hematoxylin and eosin (H&E) staining to verify the inflammatory reaction (rejection) with the counting of polymorphonuclear cells, lymphocytes, macrophages and foreign body giant cell. Masson's trichrome staining was used to verify the formation of fibrosis through the collagen area. The stem cell used was derived from fat collected from the inguinal region of the rabbit and grown in culture medium. Results: Significant changes in the eighth and twelfth week, (p = 0.032) and (p = 0.033), respectively, in polymorphonuclear cells, foreign body giant cells, macrophages and lymphocytes did not show a rejection-like inflammatory reaction that can occur in clinical transplantation, although they are increased. Collagen analysis showed no statistical difference in the studied groups, the fibrosis areas were equal to the control group. In the functional analysis of variance of pre-cystoplasty and post-cystoplasty bladder compliance, between groups, there were significant increases in the scaffold and PGA groups both seeded with mesenchymal stem cell, demonstrating that the technique allows the improvement of bladder capacity in detrusor pressure of 40 cmH20 (p = 0.049 and p = 0.013, respectively). Cystometric capacity showed no significant increase but showed a tendency to increase in the PGA group seeded with stem cell. Conclusions: Bladder enlargement techniques with implantation of extracellular matrix and PGA scaffolds, seeded or not seeded with fat-derived mesenchymal stem cell, did not generate a deleterious inflammatory reaction, called rejection, and increased bladder capacity in detrusor pressure 40 cmH20. The use of stem cells decreases inflammatory reaction in the enlarged bladder with scaffolds.
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    Calcium phosphate fibers coated with collagen: in vivo evaluation of the effects on bone repair
    (Cadernos Saude Publica, 2016) Ueno, Fabio Roberto [UNIFESP]; Kido, Hueliton Wilian [UNIFESP]; Granito, Renata Neves [UNIFESP]; Gabbai-Armelin, Paulo Roberto [UNIFESP]; Magri, Angela Maria Paiva [UNIFESP]; Fernandes, Kelly Rossetti [UNIFESP]; Silva, Antonio Carlos da; Braga, Francisco José Correa; Renno, Ana Claudia Muniz [UNIFESP]
    The aim of this study was to assess the characteristics of the CaP/Col composites, in powder and fiber form, via scanning electron microscopy (SEM), pH and calcium release evaluation after immersion in SBF and to evaluate the performance of these materials on the bone repair process in a tibial bone defect model. For this, four different formulations (CaP powder -CaPp, CaP powder with collagen -CaPp/Col, CaP fibers - CaPf and CaP fibers with collagen - CaPf/Col) were developed. SEM images indicated that both material forms were successfully coated with collagen and that CaPp and CaPf presented HCA precursor crystals on their surface. Although presenting different forms, FTIR analysis indicated that CaPp and CaPf maintained the characteristic peaks for this class of material. Additionally, the calcium assay study demonstrated a higher Ca uptake for CaPp compared to CaPf for up to 5 days. Furthermore, pH measurements revealed that the collagen coating prevented the acidification of the medium, leading to higher pH values for CaPp/Col and CaPf/Col. The histological analysis showed that CaPf/Col demonstrated a higher amount of newly formed bone in the region of the defect and a reduced presence of material. In summary, the results indicated that the fibrous CaP enriched with the organic part (collagen) glassy scaffold presented good degradability and bone-forming properties and also supported Runx2 and RANKL expression. These results show that the present CaP/Col fibrous composite may be used as a bone graft for inducing bone repair.
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    Desenvolvimento e avaliação de scaffold oriundo de tendão descelularizado
    (Universidade Federal de São Paulo (UNIFESP), 2021) Santos, Alex De Lima [UNIFESP]; Faloppa, Flavio [UNIFESP]; Universidade Federal de São Paulo
    Introduction: The use of scaffolds has considerably advanced in recent years, mainly in soft tissue injuries with large damage to the original tissue. In a way to optimize the tissue-scaffold integration, the research of decellularized scaffold is growing. Objective: This paper aimed to produce and evaluate decellularized tendon scaffolds from biomechanical, microscopic, macroscopic, and in vivo perspectives in rabbits. Methods: Thirty-six tendons from adult New Zealand rabbits were used: 11 were used as controls, and 25 were decellularized (Scaffold). The groups were subjected to histological, biomechanical, and macroscopic analyses, and the scaffold was submitted to an additional in vivo evaluation. In this evaluation, we have used eight additional rabbits in the experimental model of a bilateral rotator cuff tear and insertion of the scaffold on one side and the contralateral used as a control. Results: The scaffold showed alteration in the architecture; we have noted it with the increment of intra/inter-fascicular distance, and no change in the parallelism of ECM. And a substantial loss of nuclear material, we have established it in the reduction and disorganization of remaining nuclear material. In the biomechanical analysis, no significant differences were found after analysing the ultimate tensile load, stiffness, and elongation at the ultimate tensile load. During the in vivo evaluation was noted progressive cell infiltration in the scaffold. Conclusion: The evaluated decellularization protocol made a tendon scaffold, maintained the most important biomechanical characteristics, and permitted progressive tissue integration, when it was used in an augmentation function.
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    Desenvolvimento e caracterização de scaffolds porosos de quitosana visando aplicações biomédicas
    (Universidade Federal de São Paulo (UNIFESP), 2019-03-28) Ernesto, Julia Vaz [UNIFESP]; Lopes, Patricia Santos [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The development of scaffolds, obtained from biodegradable materials, is a point of great interest in tissue bioengineering. A bioactive material is considered a cell biocondutor when it acts as a temporary fill element guiding the local cellular activity. Chitosan is a biomaterial with several biological properties that allow the elaboration of a scaffold with satisfactory qualities, presenting coagulant and analgesic effect and is biocompatible and biodegradable. Such qualities conduct the use of the same as three-dimensional support aimed at restoration or reconstitution of tissues. Patients who present the clinical condition of severe skin lesion may opt for the application of skin substitutes or dressings developed from biomaterials. The possible use of these bio-curatives provides a possibility of an accessible and effective treatment option. In this context, a biomaterial with adequate properties to be used as cell growth support was developed. The method consisted of preparing a dispersion of 2% (w / v) chitosan in acetic acid, followed by freezing and freeze-drying. Some samples were kept chemically unchanged and used as crosslinker control, and others were crosslinked with 0.01 mol / L epichlorohydrin for 24 hours being washed and re-frozen and lyophilized. Intercalated to this process, a scaffold neutralization procedure was carried out, resulting in crosslinking by ionic interactions in the polymer network, and characteristics as promising as those of the chemically crosslinked with epichlorohydrin. Scanning electron microscopy showed that the porous morphology of crosslinked chitosan scaffolds promoted controlled formation of the polymer network, conferring properties such as adequate vapor permeability (on average, 107 g.mm/dia.m².kPa), adequate permeation to simulated fluid between 2000 and 2500g / m².day and porosity with interconnection which allows fluid absorption capacity above 900%. The crosslinking processes also favored a better mechanical resistance to the handling, corroborated by the biodegradation tests. In the biological field, although no inhibitory activity was observed for growth of microorganisms in the plates, the samples did not allow the permeation of these to the internal environment, forming an efficient barrier against contaminations. They do not present cytotoxicity, guaranteeing safety and confirming the biocompatibility of the frameworks, and allowed satisfactory cell adhesion and proliferation. Results of the tests showed that the crosslinked framework with epichlorohydrin and treated with the sodium bicarbonate neutralizer have statistically equivalent and satisfactory characteristics to be used as a bio-curative, and it is possible to obtain a functional and equivalent dermo-epidermal equivalent for treatment of different pathologies In addition it can provide an efficient and practical system for in vitro toxicological evaluation, replacing the use of animals in the research of pharmaceuticals and cosmetics fields.
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    Evaluation of chitosan-GP hydrogel biocompatibility in osteochondral defects: an experimental approach
    (Biomed Central Ltd, 2014-08-27) Martins, Edivaldo A. N.; Michelacci, Yara M. [UNIFESP]; Baccarin, Raquel Yvonne Arantes [UNIFESP]; Cogliati, Bruno; Silva, Luis C. L. C.; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    Background: Articular cartilage, because of its avascular nature, has little capacity for spontaneous healing, and tissue engineering approaches, employing different biomaterials and cells, are under development. Among the investigated biomaterials are the chitosan-based hydrogels. Although thoroughly studied in other mammalian species, studies are scarce in equines. So, the aim of the present study was to investigate the biocompatibility of chitosan-GP in horse joints submitted to high mechanical loads.Results: An osteochondral defect was created by arthroscopy in the medial surface of lateral trochlea of talus of left or right leg, randomly selected, from six healthy geldings. the defect was filled up with chitosan-GP. the contralateral joint received an identical defect with no implant. the chondral fragment removed to produce the defect was collected, processed and used as the Initial sample (normal cartilage) for histology, immunohistochemistry, and metabolic labelling of PGs. After 180 days, the repair tissues were collected, and also analyzed. At the end of the experiment (180 days after lesion), the total number of cells per field in repair tissues was equal to control, and macrophages and polymorphonuclear cells were not detected, suggesting that no significant inflammation was present. These cells were able to synthesize type II collagen and proteoglycans (PGs). Nevertheless, the cell population in these tissues, both in presence of chitosan-GP and in untreated controls, were heterogeneous, with a lower proportion of type II collagen-positives cells and some with a fibroblastic aspect. Moreover, the PGs synthesized in repair tissues formed in presence or absence of chitosan-GP were similar to those of normal cartilage. However, the chitosan-GP treated tissue had an disorganized appearance, and blood vessels were present.Conclusions: Implanted chitosan-GP did not evoke an important inflammatory reaction, and permitted cell growth. These cells were able to synthesize type II collagen and PGs similar to those synthesized in normal cartilage and in healing tissue without implant, indicating its chondrocyte nature.
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    Histopathological, cytotoxicity and genotoxicity evaluation of Biosilicate (R) glass-ceramic scaffolds
    (Wiley-Blackwell, 2013-03-01) Kido, Hueliton Wilian; Oliveira, Poliani de; Parizotto, Nivaldo Antonio; Crovace, Murilo Camuri; Zanotto, Edgar Dutra; Peitl-Filho, Oscar; Fernandes, Kristianne Porta Santos; Mesquita Ferrari, Raquel Agnelli; Ribeiro, Daniel Araki [UNIFESP]; Renno, Ana Claudia Muniz [UNIFESP]; Universidade Federal de São Carlos (UFSCar); Nove de Julho Univ UNINOVE; Universidade Federal de São Paulo (UNIFESP)
    This study evaluated the biocompatibility of Biosilicate (R) scaffolds by means of histopathological, cytotoxicity, and genotoxicity analysis. the histopathologic analysis of the biomaterial was performed using 65 male rats, distributed into the groups: control and Biosilicate (R), evaluated at 7, 15, 30, 45, and 60 days after implantation. the cytotoxicity analysis was performed by the methyl thiazolyl tetrazolium (MTT) assay, with various concentrations of extracts from the biomaterial in culture of osteoblasts and fibroblasts after 24, 72, and 120 h. the genotoxicity analysis (comet assay) was performed in osteoblasts and fibroblasts after contact with the biomaterial during 24, 72, and 96 h. in the histopathology analysis, we observed a foreign body reaction, characterized by the presence of granulation tissue after 7 days of implantation of the biomaterial, and fibrosis connective tissue and multinucleated giant cells for longer periods. in the cytotoxicity analysis, extracts from the biomaterial did not inhibit the proliferation of osteoblasts and fibroblasts, and relatively low concentrations (12.5% and 25%) stimulated the proliferation of both cell types after 72 and 120 h. the analysis of genotoxicity showed that Biosilicate (R) did not induce DNA damage in both lineages tested in all periods. the results showed that the Biosilicate (R) scaffolds present in vivo and in vitro biocompatibility. (C) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 667673, 2013.
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    Parylene scaffold for cartilage lesion
    (Springer, 2017) da Silveira Franciozi, Carlos Eduardo [UNIFESP]; Vangsness, Carleton Thomas, Jr.; Martinez, Juan Carlos; Rodger, Damien; Chou, Tzu-Chieh; Tai, Yu-Chong; Brant, Rodrigo [UNIFESP]; Wu, Ling; Abdalla, Rene Jorge [UNIFESP]; Han, Bo; Evseenko, Denis; Humayun, Mark
    Evaluate parylene scaffold feasibility in cartilage lesion treatment, introducing a novel paradigm combining a reparative and superficial reconstructive procedure. Fifteen rabbits were used. All animals had both knees operated and the same osteochondral lesion model was created bilaterally. The parylene scaffold was implanted in the right knee, and the left knee of the same animal was used as control. The animals were euthanized at different time points after surgery: four animals at three weeks, three animals at six weeks, four animals at nine weeks, and four animals at 12 weeks. Specimens were analyzed by International Cartilage Repair Society (ICRS) macroscopic evaluation, modified Pineda histologic evaluation of cartilage repair, and collagen II immunostaining. Parylene knees were compared to its matched contra-lateral control knees of the same animal using the Wilcoxon matched-pairs signed rank. ICRS mean +/- SD values for parylene versus control, three, six, nine and twelve weeks, respectively: 7.83 +/- 1.85 versus 4.42 +/- 1.08, p = 0.0005
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    Produção De Scaffolds De Poli(3-Hidroxibutirato-Co-3-Hidroxivalerato) Reforçados Com Nanocristais De Celulose Para Engenharia De Tecido
    (Universidade Federal de São Paulo (UNIFESP), 2017-12-15) Montanheiro, Thais Larissa Do Amaral [UNIFESP]; Lemes, Ana Paula [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    This work had as objective the production and characterization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and cellulose nanocrystals (CNC) scaffolds, by thermally induced phase separation (TIPS), for application in the area of tissue engineering. The effect of two modifications on CNC’s surface on the final properties of the scaffolds was evaluated, one of them being acetylation of CNC (CNC-Ac) and the other, the adsorption of polyethylene glycol (CNC-PEG). Both modifications were characterized and confirmed by transmission electron microscopy (TEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), zeta potential and thermogravimetry (TGA). TEM images showed the presence of agglomerates for CNC-Ac and CNC-PEG, confirming the reduction of hydrophilicity. On FTIR were observed new bands confirming the acetylation reaction, but the adsorption of PEG could not be confirmed by FTIR. The crystallinity index, obtained by XRD, was reduced about 12% after acetylation, and 18% after pegylation. Zeta potential of both samples was also changed, in both cases to more positive values. The thermal stability was reduced after both functionalizations, being more affected after the adsorption of PEG. The scaffolds were produced with 6% w/v PHBV/dioxane and using quenching temperature of -43 ± 2 °C. PHBV, PHBV/CNC, PHBV/CNC-Ac and PHBV/CNC-PEG scaffolds were then produced with concentrations of 1, 2 and 3 wt% of CNC, CNC-Ac and CNC-PEG. Morphological analysis showed that the scaffolds presented porous structure and interconnected pores. The introduction of CNC, CNC-Ac and CNC-PEG caused reduction in porosity values due to the changes in the solution behavior during phase separation. It was also detected that the nanoparticles could not be well dispersed in the samples. The addition of CNC, CNC-Ac and CNC-PEG caused, in general, a slight increase in the crystallinity degree the scaffolds. In the uniaxial compression tests were obtained values compatible for application as human articular cartilage, spinal disc, trabecular bone and skin. Gas chromatography analysis showed that there is no residual solvent in the scaffolds, and this result was confirmed by the cell viability assays, which showed lack of cytotoxicity in the samples, and stimulated cell proliferation/activity, with cell viability values above 84%.
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    Produção e caracterização de scaffolds de β-TCP/BG45S5 pelo método da réplica
    (Universidade Federal de São Paulo, 2019-11-25) Nakazone, Ricardo Kendy [UNIFESP]; Trichês, Eliandra de Sousa [UNIFESP]; http://lattes.cnpq.br/1619405333024881; http://lattes.cnpq.br/1662371994960832
    O envelhecimento da população vem ocasionando o aumento na demanda por infraestrutura na área da saúde, principalmente quanto à doença e defeito do tecido ósseo, uma vez que os idosos são os principais afetados. Dentro deste contexto, nas últimas décadas surgiu a engenharia tecidual, que propõe a utilização de estruturas tridimensionais e porosas denominados scaffolds para auxiliar no tratamento de tecido ósseo danificado. Os scaffolds são produzidos com biomateriais com características bioativas, biodegradáveis e biocompatíveis. Dentre os biomateriais utilizados na produção de scaffolds, o β-TCP se destaca devido sua estrutura química ser semelhante a parte mineral de ossos e dentes. Uma das formas de se obter o scaffold é pelo método da réplica, sendo um método simples e de baixo custo. Para isso, é realizada a impregnação de uma matriz polimérica (esponja) em uma suspensão cerâmica, seguida de um tratamento térmico para degradação da esponja. Desta forma, é obtido um scaffold cerâmico com estrutura idêntica à matriz utilizada. Entretanto o método apresenta desvantagem de produzir scaffold com baixa resistência a compressão, o que limita sua aplicação em regiões que demandam esforço mecânico. Uma maneira de minimizar este problema é adicionando aditivos que auxiliem na sinterização do scaffold, aumentando sua densificação. O objetivo deste trabalho é produzir scaffolds de β-TCP pelo método da réplica reforçados com biovidro 45S5, visando melhorar as propriedades do material. Os scaffolds produzidos neste trabalho apresentaram uma aparência física adequada, com poros interconectados e com dimensões ideais para aplicação. A adição de 5 wt.% de Biovidro 45S5 pode ter proporcionado a formação da renanita, NaCaPO4, um material capaz de elevar a bioatividade, liberando íons de cálcio. Entretanto a adição de biovidro não foi capaz de aumentar a resistência mecânica de compressão dos scaffolds, impossibilitando os scaffolds de serem aplicados em regiões que demandam grande esforço mecânico.