RESUMO
The effect of radiation processing and filler morphology on the biodegradation and biomechanical stability of a poly(propylene fumarate)/hydroxyapatite composite was investigated. Radiation processing influenced both cross-linking and biodegradation of the composites. Irradiation with a dose of 3 Mrad resulted in enhanced cross-linking, mechanical properties and a higher storage modulus which are favourable for dimensional stability of the implant. The particle morphology of the added hydroxyapatite in the highly cross-linked state significantly influenced the biomechanical and interfacial stability of the composites. Reorganization of agglomerated hydroxyapatite occurred in the cross-linked polymeric matrix under dynamic mechanical loading under simulated physiological conditions. Such a reorganization may increase the damping characteristics of the composite.
Assuntos
Materiais Biocompatíveis/química , Líquidos Corporais/química , Durapatita/química , Poliésteres/química , Polipropilenos/química , Materiais Biocompatíveis/efeitos da radiação , Líquidos Corporais/efeitos da radiação , Cristalização/métodos , Relação Dose-Resposta à Radiação , Durapatita/efeitos da radiação , Módulo de Elasticidade/efeitos da radiação , Raios gama , Dureza/efeitos da radiação , Temperatura Alta , Teste de Materiais , Poliésteres/efeitos da radiação , Polipropilenos/efeitos da radiação , Doses de Radiação , Propriedades de Superfície/efeitos da radiaçãoRESUMO
The effect of hydroxyapatite (HAP) on the performance of nanocomposites of an unsaturated polyester, i.e., hydroxy-terminated high molecular weight poly(proplyene fumarate) (HT-PPFhm), was investigated. A thermoset nanocomposite was prepared with nanoparticles of calcined HAP (<100 nm, rod-like shape, filler content 30 wt.%), HT-PPFhm and N-vinyl pyrrolidone, dibenzoyl peroxide and N,N-dimethyl aniline. Two more nanocomposites were prepared with precipitated HAP nanoparticles (<100 nm rod-like shape) and commercially available HAP nanoparticles (<200 nm spherical shape), respectively. Calcined HAP nanoparticles resulted in very good crosslinking in the resin matrix with high crosslinking density and interfacial bonding with the polymer, owing to the rod-like shape of the nanoparticles; this gave improved biomechanical strength and modulus and also controlled degradation of the nanocomposite for scaffold formation. The tissue compatibility and osteocompatibility of the nanocomposite containing calcined HAP nanoparticles was evaluated. The tissue compatibility was studied by intramuscular implantation in a rabbit animal model for 3 months as per ISO standard 10993/6. The in vivo femoral bone repair was also carried out in the rabbit animal model as per ISO standard 10993/6. The nanocomposite containing calcined HAP nanoparticles is both biocompatible and osteocompatible.
Assuntos
Implantes Absorvíveis , Substitutos Ósseos/química , Durapatita/química , Fraturas do Fêmur/patologia , Fraturas do Fêmur/cirurgia , Fumaratos/química , Nanoestruturas/química , Polipropilenos/química , Animais , Módulo de Elasticidade , Dureza , Teste de Materiais , Nanoestruturas/ultraestrutura , Equipamentos Ortopédicos , Coelhos , Resultado do TratamentoRESUMO
Biodegradable and injectable hydroxy terminated-poly propylene fumarate (HT-PPF) bone cement was developed. The injectable formulation consisting HT-PPF and comonomer, n-vinyl pyrrolidone, calcium phosphate filler, free radical catalyst, accelerator and radiopaque agent sets rapidly to hard mass with low exothermic temperature. The candidate bone cement attains mechanical strength more than the required compressive strength of 5 MPa and compressive modulus 50 MPa. The candidate bone cement resin elicits cell adhesion and cytoplasmic spreading of osteoblast cells. The cured bone cement does not induce intracutaneous irritation and skin sensitization. The candidate bone cement is tissue compatible without eliciting any adverse tissue reactions. The candidate bone cement is osteoconductive and inductive and allow osteointegration and bone remodeling. HT-PPF bone cement is candidate bone cement for minimally invasive radiological procedures for the treatment of bone diseases and spinal compression fractures.
Assuntos
Materiais Biocompatíveis/química , Procedimentos Cirúrgicos Minimamente Invasivos , Procedimentos Ortopédicos/métodos , Biodegradação Ambiental , Fenômenos Biomecânicos , Líquidos Corporais , Cimentos Ósseos/química , Regeneração Óssea , Fosfatos de Cálcio/química , Adesão Celular , Linhagem Celular Tumoral , Força Compressiva , Meios de Contraste/química , Reagentes de Ligações Cruzadas/química , Fumaratos/análise , Fumaratos/síntese química , Fumaratos/química , Guias como Assunto/normas , Dureza , Humanos , Concentração de Íons de Hidrogênio , Injeções , Teste de Materiais , Estrutura Molecular , Osseointegração , Osteoblastos/metabolismo , Osteoblastos/ultraestrutura , Osteossarcoma/patologia , Polipropilenos/análise , Polipropilenos/síntese química , Polipropilenos/química , Pirrolidinonas/química , Espectroscopia de Infravermelho com Transformada de Fourier , TemperaturaRESUMO
Biodegradable hydroxyl terminated-poly(castor oil fumarate) (HT-PCF) and poly(propylene fumarate) (HT-PPF) resins were synthesized as an injectable and in situ-cross linkable polyester resins for orthopedic applications. An injectable adhesive formulation containing this resin blend, N-vinyl pyrrolidone (NVP), hydroxy apatite, free radical initiator and accelerator was developed. The Composite adhesives containing the ratio of resin blend and NVP, 2.1:1.5, 2.1:1.2 and 2.1:1.0 set fast with tolerable exothermic temperature as a three dimensionally cross linked toughened material. Crosslink density and mechanical properties of the crosslinked composite increase with increase of NVP. The present crosslinked composite has hydrophilic character and cytocompatibility with L929 fibroblast cells.
