RESUMO
Reconstruction of critical sized bone injuries is a major problem that continues to inspire the design of new materials and grafts. Natural ceramics (hydroxyapatite (HA) coralline HA, or synthetic HA) and ß-tricalcium phosphate (ß-TCP) are being explored for use as scaffolds in bone tissue engineering, among several other materials. The present study evaluated the bone forming capacity of nanosize bioceramics synthesized in situ in poly-vinyl alcohol (PVA) with different ratios of HA and ß-TCP; the Ca/P ratio was 1.62 for bioceramic P1, 1.60 for P2 and 1.58 for P3. Further osteogenesis in vitro with mesenchymal stem cells (MSC) acquired from different sources for osteogenesis in vitro and their bone healing properties in vivo were also evaluated. MSC isolated from human placenta, Wharton's jelly from umbilical cord, fetal bone marrow and adipose tissue, cultured in the presence of nanosize bioceramic particles, were monitored for osteogenic differentiation. Placental cells showed the best osteogenic potential of the different MSC studied on the basis of expression of osteogenic markers. Complete regeneration of the damaged region was observed in vivo when MSC derived from placenta were used with nanoceramic (Ca/P ratio 1.58) in the experimental defect created in the femur of Wistar rats. Even small variation in the Ca/P ratio can alter the outcome of tissue constructs.
Assuntos
Osso e Ossos , Fosfatos de Cálcio , Cerâmica , Nanopartículas , Engenharia Tecidual , Fosfatase Alcalina/metabolismo , Animais , Sequência de Bases , Células Cultivadas , Primers do DNA , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/enzimologia , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo RealRESUMO
The present study describes the efficacy of the glycine-poly(vinyl)alcohol ferrofluid as a contrast enhancer for Magnetic resonance imaging. Interaction between inorganic minerals and biomolecules are extremely unique and interesting. The results demonstrate that ferro fluids can be a good contrast enhancer for Magnetic Resonance Imaging as seen in the very first results after MRI studies.
Assuntos
Materiais Biomiméticos/farmacocinética , Barreira Hematoencefálica/metabolismo , Compostos Férricos/farmacocinética , Glicina/química , Álcool de Polivinil/química , Animais , Materiais Biomiméticos/síntese química , Barreira Hematoencefálica/anatomia & histologia , Meios de Contraste/química , Meios de Contraste/farmacocinética , Compostos Férricos/química , Imageamento por Ressonância Magnética/métodos , RatosRESUMO
In situ synthesized hydroxyapatite-poly(vinyl) alcohol nanocomposite was subjected to microwave irradiation, post synthesis. Interestingly, the aging time of 1 week required for the normal biomimetic process was reduced to 1 h post microwave irradiation, as characterized by x-ray powder diffraction and transmission electron microscopy. The surface topography shows the tendency of tubules to cross-link with the help of microwave energy. The microwave energy seems to provide a directional pull to the polymer chains which could have led to an enhancement of the kinetics of phase formation.
Assuntos
Materiais Biomiméticos/química , Materiais Biomiméticos/efeitos da radiação , Substitutos Ósseos/química , Durapatita/química , Durapatita/efeitos da radiação , Nanoestruturas/química , Nanoestruturas/efeitos da radiação , Substitutos Ósseos/efeitos da radiação , Cristalização/métodos , Cinética , Teste de Materiais , Micro-Ondas , Nanoestruturas/ultraestrutura , Doses de RadiaçãoRESUMO
Hydroxyapatite-poly (vinyl) alcohol nanocomposite powder was synthesized using varying poly (vinyl) alcohol concentrations. The dried powder was compacted into micro-porous disks at a load of 4 tons. The disks were sintered at 1200 degrees C to evolve porous nanocomposites. Size and shape of the pores observed in the scanning electron micrographs were quantified by using image processing software. Ultrasound velocity measurements were done to evaluate mechanical properties non-destructively.
Assuntos
Durapatita/química , Teste de Materiais/métodos , Nanocompostos/química , Álcool de Polivinil/química , Estresse Mecânico , Materiais Biocompatíveis/química , Fenômenos Biomecânicos/fisiologia , Força Compressiva , Módulo de Elasticidade , Polímeros/química , Porosidade , Propriedades de Superfície , Difração de Raios XRESUMO
Transparent and stable Poly(vinyl alcohol) hydrogels were synthesized from polymer aqueous solution without resorting to a mixed solvent such as dimethyl sulfoxide and water. Contrary to the reported methods involving hydrogen bond induced physical crosslinking by repeated freeze-thawing at -20 degrees C, the present process demonstrates the gelation taking place at relatively higher temperature, i.e. 0 degrees C. While maintaining transparency in all the synthesized hydrogels, the present paper reports systematic structural and morphological variations in the hydrogels as a function of polymer concentration.
Assuntos
Hidrogéis/química , Álcool de Polivinil/química , Varredura Diferencial de Calorimetria , Cristalização , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Pós , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios XRESUMO
Biphasic calcium phosphate nanoparticles comprising both hydroxyapatite (HA) and beta polymorph of tricalcium phosphate (beta-TCP) have been synthesized together by a polymer matrix mediated process. The process, based on in situ mineralization of poly (vinyl alcohol), exerts a good control over the morphological features of biphasic nanoparticles. By controlling the reaction chemistry (Ca:P ratios), nanobioceramic particles having three different HA/beta-TCP ratios of 50:50, 55:45 and 60:40 respectively. As the two constituents of biphasic system (HA and beta-TCP) facilitate series of signaling cascades in osteoblast division and differentiation, the adhesion and differentiation properties of mesenchymal cells (MSCs) derived from bone marrow has been studied.