RESUMO
Bone substitutes are required to repair osseous defects caused by a number of factors, such as traumas, degenerative diseases, and cancer. Autologous bone grafting is typically used to bridge bone defects, but suffers from chronic pain at the donor-site and limited availability of graft material. Tissue engineering approaches are being investigated as viable alternatives, which ideal scaffold should be biocompatible, biodegradable, and promote cellular interactions and tissue development, need to present proper mechanical and physical properties. In this study, poly(ε-caprolactone) (PCL), oleic acid (OA) and hydroxyapatite (HAp) were used to obtain films whose properties were investigated by contact angle, scanning electron microscopy, atomic force microscopy, tensile mechanical tests, and in vitro tests with U2OS human osteosarcoma cells by direct contact. Our results indicate that by using OA as surfactant/dispersant, it was possible to obtain a homogenous film with HAp. The PCL/OA/Hap sample had twice the roughness of the control (PCL) and a lower contact angle, indicating increased hydrophilicity of the film. Furthermore, mechanical testing showed that the addition of HAp decreased the load at yield point and tensile strength and increased tensile modulus, indicating a more brittle composition vs. PCL matrix. Preliminary cell culture experiments carried out with the films demonstrated that U2OS cells adhered and proliferated on all surfaces. The data demonstrate the improved dispersion of HAp using OA and the important consequences of this addition on the composite, unveiling the potentially of this composition for bone growth support. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1076-1082, 2016.
Assuntos
Substitutos Ósseos/química , Durapatita/química , Teste de Materiais , Ácido Oleico/química , Poliésteres/química , Tensoativos/química , Adesão Celular , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Engenharia TecidualRESUMO
We investigated the potential use of 3D hybrid membrane: poly (ε-caprolactone) (PCL) mesh using rotary jet spinning with subsequent chitosan (CH) coating. The morphological examinations by scanning electron microscopy (SEM) were proved the efficiency of this technique on obtaining relative homogeneous PCL fiber mats (15,49±4,1µm), with high surface porosity (1,06±0,41µm) and effective CH coating. The feasibility of rotary jet spinning allowed the solvent evaporation during the process; this fact was verified by differential scanning calorimetry (DSC), indeed also had verified changes in thermal properties on the hybrid membrane, since the present of CH. It was investigated the mechanical properties of the hybrid membrane and CH film, the data were that the samples presents good tensile modulus but low strain at the break. In addition, it was verified the biocompatibility properties in vitro using Vero cells. PCL mesh demonstrated cells more spread vastly in the pore surface, with attachments in between fibers indicating the potential for cell adhesion. The films samples (CH and hybrid membrane) resulted in a cells layer on the surfaces with an intense staining (metachromasy), which is the result of cells more active. The cell counting -5 days of culture- and the MTT assay -21 days of culture- demonstrated that the materials tested proved to be different from the positive control and equal to each other and this fact, in our view, this indicates a satisfactory proliferation. Thus, based on the results here, this novel hybrid membrane provides an attractive material for tissue engineering applications.
Assuntos
Caproatos/química , Quitosana/química , Lactonas/química , Membranas Artificiais , Polímeros/química , Engenharia Tecidual/métodos , Animais , Materiais Biocompatíveis/química , Varredura Diferencial de Calorimetria , Adesão Celular , Chlorocebus aethiops , Teste de Materiais , Microscopia Eletrônica de Varredura , Porosidade , Propriedades de Superfície , Resistência à Tração , Alicerces Teciduais/química , Células VeroRESUMO
Porous bioresorbable polymers have been widely used as scaffolds in tissue engineering. Most of the bioresorbable scaffolds are aliphatic polyesters and the methods employed to prepare the porous morphology may vary. This work describes and evaluates the in vitro degradation of porous and dense scaffolds of poly(ε-caprolactone) (PCL) and poly(D,L-lactic acid-co-glycolic acid) (50/50) (PLGA50) prepared by particulate leaching-melt compression process. Biological evaluation was carried out using osteoblast cell cultures. The results showed an autocatalytic effect on the dense samples. Osteoblasts presented intermediate adhesion and the cell morphology on the surface of these materials was dispersed, which indicated a good interaction of the cells with the surface and the material.
Assuntos
Desenvolvimento Ósseo , Ácido Láctico/química , Poliésteres/química , Ácido Poliglicólico/química , Engenharia Tecidual/métodos , Alicerces Teciduais , Fenômenos Biomecânicos , Linhagem Celular , Humanos , Microscopia Eletrônica de Varredura , Osteoblastos , Copolímero de Ácido Poliláctico e Ácido PoliglicólicoRESUMO
The electrochemical behaviour of two commercial titanium alloys Ti-6Al-4 V (ASTM F136) and Ti-13Nb-13Zr (ASTM F1713) was investigated in Ringer physiological solution at two pH values (5.5 and 7.0). The corrosion properties were examined by using electrochemical techniques: Potentiodynamic anodic polarization, cyclic polarization and electrochemical impedance spectroscopy (EIS). The electrochemical corrosion properties of both alloys at different conditions were measured in terms of corrosion potential (E (corr)), corrosion current density (i (corr)) and passivation current density (i (pass)). Equivalent electrical circuits were used to modulate EIS data, in order to characterize alloys surface and better understanding the pH effect on the interface alloy/solution.
Assuntos
Materiais Biocompatíveis/química , Eletroquímica/métodos , Teste de Materiais , Modelos Químicos , Próteses e Implantes , Titânio/química , Ligas , Simulação por Computador , CorrosãoRESUMO
This work assesses the effect of lyophilization on the cytotoxicity and residual aldehyde concentration of glutaraldehyde-treated and lyophilized bovine pericardium (group A), comparing it to conventional glutaraldehyde-treated bovine pericardium (group B). Cytotoxicity was measured by incubating a pericardium sample from each group in saline and assessing the eluant's influence on cellular growth. Residual aldehydes were measured by HPLC. Although both groups' eluants exhibited some cytotoxicity, the eluant from group A was less cytotoxic, with a cytotoxicity index (IC50(%)) of 41%. Group B eluants all had marked cytotoxic effects; cell growth was 24.15% of the negative control at the most dilute eluant concentration (6.25%). The mean residual glutaraldehyde level was less in group A than in group B (2.36 +/- 0.11 and 9.90 +/- 3.70 g/l, respectively; n=3, P < 0.05), but residual formaldehyde levels did not differ. These results demonstrate that compared with conventional glutaraldehyde-treated bovine pericardium, lyophilized pericardium is less cytotoxic, with fewer glutaraldehyde residues.
Assuntos
Aldeídos/análise , Liofilização , Glutaral/toxicidade , Pericárdio/efeitos dos fármacos , Animais , Bovinos , Resíduos de DrogasRESUMO
Neste trabalho foi estudada a resposta da musculatura triceps de ratos Wistar a particulas de uma poliétersulfona fabricada pela AMOCO e vendida sob o nome comercial UDELTM P-1800 implantadas na forma de particulas por um período de até 52 semanas. Ao final do período de implante, näo foi observado pelos autores nenhum indício que indicasse toxicidade do material
Assuntos
Animais , Masculino , Sulfonas , Nervo Sural , Músculos , Material Particulado , Ratos WistarRESUMO
O objetivo deste trabalho foi o desenvolvimento de uma prótese de ventrículo artificial implantável (VAI), para utilização em pacientes com insuficiência cardíaca profunda que necessitam de assistência circulatória mecânica, como ponte para transplante de coração. Foi utilizado um programa CAD (Microstation) para o projeto mecânico do VAI. O dispositivo apresenta uma membrana livre fixada entre duas crianças de titânio, seu acionamento é do tipo pneumático. O dispositivo foi projetado para ser implantado na cavidade abdominal e conectado ao coração nativo via ápice do ventrículo esquerdo e aorta, por meio de cânulas confeccionados em silicone, acopladas a válvulas biológicas de pericárdio bovino.
Abstract - This paper describes the design of an implantable artificial ventricular assist device to support the heart as a bridge to heart transplantation, in patients with profound cardiac failure. The artificial ventricle presented has a free floating membrane, dividing two titanium carcass. The driving unit is pneumatic. Two silicone cannulae are used to conect the device to the patient's heart ( left ventricle apex and aorta). Each cannula is eqquiped with one bovine pericardium valve. A computer program (Microstation) was utilized to provide volumetric calculus, bidimensional and tridimensional visualization to optimize the design