RESUMO
Adipose-derived mesenchymal stem cells (ASCs) accelerate the osteointegration of bone grafts and improve the efficiency in the formation of uniform bone tissue, providing a practical and clinically attractive approach in bone tissue regeneration. In this work, the effect of nanofibrous biomimetic matrices composed of poly(ε-caprolactone) (PCL), nanometric hydroxyapatite (nHA) particles and 14-3-3 protein isoform epsilon on the initial stages of human ASCs (hASCs) osteogenic differentiation was investigated. The cells were characterized by flow cytometry and induction to differentiation to adipogenic and osteogenic lineages. The isolated hASCs were induced to differentiate to osteoblasts over all scaffolds, and adhesion and viability of the hASCs were found to be similar. However, the activity of alkaline phosphatase (ALP) as early osteogenic marker in the PCL-nHA/protein scaffold was four times higher than in PCL-nHA and more than five times than the measured in neat PCL.
Assuntos
Proteínas 14-3-3 , Durapatita , Células-Tronco Mesenquimais/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Poliésteres , Alicerces Teciduais/química , Proteínas 14-3-3/química , Proteínas 14-3-3/farmacologia , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Células Cultivadas , Durapatita/química , Durapatita/farmacologia , Galvanoplastia/métodos , Humanos , Teste de Materiais , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/fisiologia , Nanofibras/química , Osteoblastos/efeitos dos fármacos , Osteoblastos/fisiologia , Osteogênese/fisiologia , Poliésteres/química , Poliésteres/farmacologia , Gordura Subcutânea Abdominal/citologia , Propriedades de Superfície/efeitos dos fármacos , Engenharia Tecidual/métodosRESUMO
Tramadol is an analgesic usually prescribed for the management of pain, with a certain risk of addiction in chronic patients. The incorporation of tramadol in sustained-release systems results particularly attractive for the administration of accurate doses. In this work, emulsion electrospinning was used for the preparation of tramadol-loaded nanofibrous membranes based on poly(ε-caprolactone). Compositional and processing parameters were screened and evaluated in terms of the morphology of the resulting nanofibers, encapsulation efficiency and drug release in time. The polymer concentration, surfactant type and amount, and the homogenization rate used for the emulsions preparation were found to greatly affect the fluid stability and the resulting materials structure and functionality. The intrinsic features of the starting fluid studied in this work played a significant role for the modulation of tramadol release from nanofibrous matrices. The use of sodium dodecyl sulfate as surfactant with an optimal homogenization rate allowed the preparation of electrospun fibrous membranes with good encapsulation efficiency, a minimal burst release and a sustained delivery of tramadol in time.
Assuntos
Emulsões/química , Engenharia Tecidual/métodos , Tramadol/farmacologia , Preparações de Ação Retardada/farmacologia , Liberação Controlada de Fármacos , Membranas Artificiais , Tamanho da Partícula , Tensoativos/química , Termogravimetria , Difração de Raios XRESUMO
Two series of biomedical segmented polyurethanes (SPU) based on poly(epsilon-caprolactone) diol (PCL diol), 1,6-hexamethylene diisocyanate (HDI) or L: -lysine methyl ester diisocyanate (LDI) and three novel chain extenders, were synthesized and characterized. Chain extenders containing urea groups or an aromatic amino-acid derivative were incorporated in the SPU formulation to strengthen the hard segment interactions through either bidentate hydrogen bonding or pi-stacking interactions, respectively. By varying the composition of the hard segment (diisocyanate and chain extender), its structure was varied to investigate the structure-property relationships. The different chemical composition and symmetry of hard segment modulated the phase separation of soft and hard domains, as demonstrated by the thermal behavior. Hard segment association was more enhanced by using a combination of symmetric diisocyanate and urea-diol chain extenders. The hard segment cohesion had an important effect on the observed mechanical behavior. Polyurethanes synthesized using HDI (Series H) were stronger than those obtained using LDI (Series L). The latter SPU exhibited no tendency to undergo cold-drawing and the lowest ultimate properties. Incorporation of the aromatic chain extender produced opposite effects, resulting in polyurethanes with the highest elongation and tearing energy (Series H) and the lowest strain at break (Series L). Since the synthesized biodegradable SPU possess a range of thermal and mechanical properties, these materials may hold potential for use in soft tissue engineering scaffold applications.
Assuntos
Materiais Biocompatíveis/química , Poliésteres/química , Poliuretanos/química , Materiais Biocompatíveis/síntese química , Fenômenos Biomecânicos , Cianatos/química , Isocianatos , Espectroscopia de Ressonância Magnética , Teste de Materiais , Estrutura Molecular , Poliésteres/síntese química , Poliuretanos/síntese química , Espectroscopia de Infravermelho com Transformada de Fourier , Resistência à Tração , TermodinâmicaRESUMO
This work describes the preparation, physicochemical characterization, mechanical properties and in vitro biological properties of two bioresorbable aliphatic segmented poly(esterurethane urea)s (SPEUU) based on poly(epsilon-caprolactone) diol (PCL diol), 1,6-hexamethylene diisocyanate and two novel urea-diol chain extenders. To strengthen the interactions through hydrogen bonding in the hard segments of SPEUU, novel chain extenders containing urea groups were synthesized and used in the SPEUU formulation. The different chemical structures of the chain extenders modulated the phase separation of soft and hard segments, as demonstrated by the thermal behavior. The hard segment association was enhanced using a diurea-diol chain extender. The biological interactions between the obtained materials and blood were studied by in vitro methods. Research on the protein adsorption, platelet adhesion and thrombus formation is presented. Studies of protein adsorption onto polymeric surfaces showed that SPEUU adsorbed more albumin than fibrinogen. Studies on platelet adhesion and thrombus formation of SPEUU-coated coverslips indicated the antithrombogenic behavior of these surfaces. The synthesized SPEUU revealed no signs of cytotoxicity to Chinese hamster ovary cells, showing satisfactory cytocompatibility.
Assuntos
Poliuretanos/síntese química , Ureia/síntese química , Adsorção , Adulto , Animais , Células CHO , Varredura Diferencial de Calorimetria , Morte Celular/efeitos dos fármacos , Cricetinae , Cricetulus , Fibrinogênio/metabolismo , Humanos , Cinética , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Selectina-P/metabolismo , Adesividade Plaquetária/efeitos dos fármacos , Poliuretanos/química , Poliuretanos/farmacologia , Albumina Sérica/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Ressonância de Plasmônio de Superfície , Trombose , Ureia/química , Ureia/farmacologiaRESUMO
New acrylic-based cements were formulated by replacing a mass fraction of 20% of poly(methyl methacrylate) (PMMA) powder by PMMA/poly(epsilon-caprolactone) (PCL) beads (throughout this article all compositions are given as mass fractions, unless specified otherwise). PMMA/PCL beads containing 10 and 30% PCL were synthesized by suspension polymerization. Cements were prepared by replacing part of the PMMA powder of the formulation by an equivalent mass of PMMA/PCL particles. The influence of the PCL content in the beads on the mechanical behavior was assessed by testing the cements in flexure and compression. The addition of PMMA/PCL particles with 10% PCL content resulted in a marked increase in both flexural modulus and flexural strength related to the plain PMMA beads formulation. This improvement was attributed to a decrease in the cured material porosity. Conversely, by the incorporation of beads with 30% PCL content the flexural properties decreased. This behavior was attributed to the debonding of the particles from the matrix, which was revealed by SEM images. The observed compressive yield strength decrease with the increase of PCL content in the beads was attributed to a low degree of adhesion between the heterogeneous particles and the matrix as well as to the plasticizing effect of the PCL.
Assuntos
Cimentos Ósseos/química , Poliésteres/química , Polimetil Metacrilato/química , Teste de Materiais , Mecânica , Microscopia Eletrônica de Varredura , Propriedades de SuperfícieRESUMO
Cross-linked PMMA beads were prepared with the use of two cross-linking agents with different chain lengths: triethylene glycol dimethacrylate (TEGDMA) and poly(ethylene glycol) dimethacrylate (PEGDMA). Beads containing 10 wt % TEGDMA and 2, 5, and 10 wt % PEGDMA were synthesized by suspension polymerization. Experimental cement formulations were prepared by replacing part of the PMMA powder phase by an equivalent weight of the cross-linked beads. The mechanical behavior of the modified cements was carried out by testing the cements in flexure and compression. All cements displayed a higher flexural modulus, which was accompanied with a slight decrease in the flexural strength. The two-parameter Weibull model, which was used to analyze the flexural strength data, gave a good representation of the fracture load distribution. In cements prepared with beads containing 2 and 5 wt % PEGDMA and 10 wt % TEGDMA, no improvement in the flexural strength was observed. Debonding of the particles from the matrix was considered responsible for the decreased flexural strength. On the contrary, cements prepared with different proportions of beads containing 10 wt % PEGDMA resulted in a markedly increased flexural strength compared with the unmodified cement. An improved reinforcing effect of the cross-linked beads and a significant degree of bonding with the matrix in these cements account for the superior flexural strength compared with the other composite cements tested.