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Bone Implants (bone + implant)
Selected AbstractsLow Temperature Fabrication of ,-TCP,PCL Nanocomposites for Bone Implants,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Michael Bernstein Abstract A method to fabricate strong bioresorbable calcium phosphate,polymer nanocomposites with low polymer content without exposing the material to excessively high-processing temperatures is reported. Dense ,-TCP-based nanocomposites containing 5 or 15,vol% of uniformly distributed polycaprolactone (PCL) polymer were obtained by mixing ,-TCP nanopowder with PCL dissolved in chloroform followed by room temperature consolidation at the high pressure of 2.5,GPa (cold sintering). The composites had an attractive combination of compressive strength and ductility, and their dissolution behavior was similar to that of pure cold sintered ,-TCP. The immersion of ,-TCP,PCL composites in simulated body fluid (SBF) yielded in vitro deposition of a bone-like apatite layer suggesting the ability of these materials to bind to native bone tissue upon implantation. [source] Biphasic Resorbable Calcium Phosphate Ceramic for Bone Implants and Local Alendronate Delivery,ADVANCED ENGINEERING MATERIALS, Issue 5 2010Shashwat S. Banerjee A novel biphasic calcium phosphate ceramic composed of tricalcium phosphate (TCP) and calcium pyrophosphate (CP) is synthesized in order to tailor the biodegradation behavior of the ceramic. The results show that biphasic TCP/CP ceramic has a strength of 62.2,±,2.1 MPa, which is superior to single-phase TCP and CP ceramics, which show strengths of 44.3,±,3.0 and 53.0,±,4.8 MPa, respectively. In addition, biphasic TCP/CP ceramic displays a controlled strength degradation from 62.2,±,2.1 to 40.5,±,1.0 MPa in stimulated body fluid over a period of 28 d. An in vitro cell materials interaction study using human fetal osteoblast cells indicates that TCP/CP ceramic is cytocompatible. TCP/CP ceramic also show a good loading capacity for alendronate. Adsorption of alendronate (AD) on the TCP/CP surface is found to proceed via ligand exchange mechanism and the in vitro release profile of AD from TCP/CP surface is characterized by an initial fast release followed by a slow and sustained release. Strong electrostatic interactions between AD groups and surface Ca2+ ions enable the slow and sustained release of AD. These results demonstrate that the newly developed biphasic ceramic, with its controlled strength degradation and drug release, shows promise for use in orthopedic and tissue engineering applications. [source] Bone Implants: (Osteoconductive and Osteoinductive Properties of Zeolite MFI Coatings on Titanium Alloys) Adv.ADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Funct. Biocompatible zeolite anti-corrosion coatings have potential for success as bone scaffolding materials. In this work, reported by Y. Yan and co-workers, titanium-based dental implants are covered with zeolite MFI coatings to prevent against corrosion within the dental cavity. Zeolite coatings are non-toxic, and prevent the release of toxic ions from metals into tissue. The 3D micro-topology of the zeolites also enhances cell proliferation, differentiation, and surface adhesion. [source] A Computational Approach on the Osseointegration of Bone Implants Based on a Bio-Active Interface TheoryGAMM - MITTEILUNGEN, Issue 2 2009André Lutz Abstract In this presentation an integrated approach on the simulation of osseointegration in the boneimplant interface is outlined. Besides the consistent combination of computational bone remodelling simulation and established medical imaging techniques, a new model refinement in terms of a bioactive interface theory is introduced, which enables the simulation of bone ingrowth in rough coated uncemented implants. Under consideration of seven physiological loads of daily motion the bone-implant relative micromotion in a soft tissue region around the endoprosthesis is investigated. As the micromotions are an important factor for osseointegration, because excessive micromotion leads to apposition of fibrous tissue, they are considered for the simulation of osseointegration. Results for different parameter constellations, regarding thickness and stiffness of bone-implant interface layer, are compared and the ingrowth for different configurations is predicted. With these results conclusions can be made about the stability of prosthesis in the host bone, which is an important factor for the clinical success of the treatment (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Bovine Serum Albumin and Lysozyme Adsorption on Calcium Phosphate ParticlesADVANCED ENGINEERING MATERIALS, Issue 1-2 2010Berit Mueller Two model proteins that are oppositely charged at neutral pH , bovine serum albumin (BSA) and lysozyme, with acidic and alkaline isoelectric points, respectively , are used to investigate the protein adsorption behaviour of hydroxyapatite and beta-tricalcium phosphate (, -TCP) particles. Both calcium phosphate based particles are highly relevant for the fabrication of bioactive and resorbable bone implants. The investigations are carried out by combining zeta potential and Vis spectroscopy measurements. The changes of zeta potential and isoelectric point are determined as a function of added protein. Both proteins form a monolayer on , -TCP, while on hydroxyapatite only semi-monolayers were measured. For BSA, a side-on adsorption mode is suggested, whereas end-on adsorption appears to be most likely for lysozyme. The zeta potential curves as a function of adsorbed protein show that plateaus of the protein amounts adsorbed increase with charge saturation. In addition, the spatial charge distribution of both proteins is modelled to get a further understanding of the initial adsorption orientation of the biomolecules, supporting the findings from the experimental data. The reported findings can be transferred to the adsorption behaviour of a variety of proteins on calcium phosphate surfaces and are helpful for the fabrication of bone-analogous calcium phosphate/protein nanocomposites. [source] | ||||||||||