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Dresden, Germany

Khalyavina A.,Leibniz Institute of Polymer Research | Schallausky F.,InnoTERE GmbH | Kombeiy H.,Leibniz Institute of Polymer Research | Samman M.A.,Deutsches Kunststoff - Institute | And 2 more authors.
Macromolecules | Year: 2010

The synthesis and characterization of aromatic-aliphatic polyesters with tailored degree of branching (DB), i.e. hyperbranched (hb), gradually branched, and linear polymers, are described. The dilute solution properties of polymers resulting from two different synthetic approaches are compared. The ABB*/ AB2 approach leads to homopolymers with different DB based on the same AB2 monomer, 4,4-bis(4′-hydroxyphenyl)pentanoic acid, employing the protection of one phenolic group (B*) in the AB2 monomer followed by copolymerization with AB2 monomer at different molar ratios. Because of their identical chemical origin, well-tunable DB, comparable molar masses, an absence of aggregation in common solvents, and high refractive index increments, they are suitable as model systems in branching characterization. Their solution properties are compared to those of polymers obtained by the AB/AB2 approach. In order to study the influence of the end-groups on thermal and solution polymer properties, all terminal OH groups were modified with tert-butyldimethylsilyl chloride (SY-Cl). A different dependence of the thermal properties on branching was found for OH- and SY-terminated samples produced by the ABB*/AB2 approach. While the difference in the Ts values between linear and hb structures was found to be 16°C for SY-terminated samples, nearly identical values were obtained for OH-terminated linear and hb polyesters due to strong effect of hydrogen bond formation. © 2010 American Chemical Society.

Luo Y.,TU Dresden | Lode A.,TU Dresden | Sonntag F.,Fraunhofer Institute for Material and Beam Technology | Nies B.,InnoTERE GmbH | Gelinsky M.,TU Dresden
Journal of Materials Chemistry B | Year: 2013

Herein, we present a new type of biphasic organic-inorganic scaffold, which can be fabricated by multi-channel 3D plotting under mild conditions based on a highly concentrated alginate paste and a ready-to-use calcium phosphate cement (CPC) for bone and osteochondral tissue engineering. The structures of scaffolds were characterised by light and scanning electron microscopy (SEM). Results indicated that the concentrated alginate and CPC pastes had comparable plotting consistency, and therefore could be combined in one (biphasic) scaffold by applying predesigned plotting parameters. After crosslinking of alginate and setting of CPC, the biphasic scaffold obtained mechanical and structural stability. Mechanical test data revealed that biphasic CPC-alginate scaffolds had significantly increased compressive strength and modulus compared to pure alginate as well as mixed calcium phosphate (CaP)-alginate scaffolds in a wet state and improved strength and toughness compared to pure CPC scaffolds in both dry and wet conditions. Culture of human mesenchymal stem cells (hMSCs) on these scaffolds over 3 weeks demonstrated the good cytocompatibility of the selected materials. Because of the mild preparation conditions, bovine serum albumin (BSA) as a model protein was loaded in alginate and CPC pastes prior to plotting with high loading efficiency. Release studies in vitro showed that BSA released much faster from alginate strands than from CPC strands, which might allow amount-controlled protein release from biphasic CPC-alginate scaffolds. Furthermore, an upgraded bipartite osteochondral scaffold consisting of an alginate part for chondral and a biphasic CPC-alginate part for bony repair was fabricated based on this technique. This scaffold showed a strong organic-inorganic interface binding due to interlocking and crosslinking of the alginate strands. This journal is © 2013 The Royal Society of Chemistry.

The invention relates to a bone implant which comprises a magnesium-containing metallic material having a reduced corrosion rate and inorganic bone cement, and to methods and a kit for producing the bone implant. With a method according to the invention, it is possible to obtain a bone implant which comprises inorganic bone cement and a magnesium-containing metallic material with a corrosion-inhibiting coating which contains magnesium-ammonium phosphates. In the method according to the invention, a magnesium-containing metallic material, of which the surface has a magnesium oxide layer and/or a magnesium salt layer, is combined with inorganic bone cement in order to generate a solid composite material that comprises the inorganic bone cement and the magnesium-containing metallic material. The inorganic bone cement contains inorganic powder constituents, which set in the presence of water to form a solid, and water-soluble phosphate-ion-containing salts, preferably water-soluble phosphate-ion-containing and ammonium-ion-containing salts. According to the invention, the magnesium-containing metallic material is brought into contact with water before and/or during the combination with the inorganic bone cement in the presence pt of water-soluble ammonium-ion-containing and phosphate-ion-containing salts. Moreover, the inorganic bone cement is set by being brought into contact with water.

The invention relates to methods for producing a partial or complete bioactive coating of an iron and/or zinc based metal implant material with calcium phosphates, a bioactively coated iron and/or zinc based metal implant, which is partially or completely coated with calcium phosphates, and bone implants containing an implant material according to the invention. In order to produce the coating according to the invention, iron and/or zinc based metal implant materials are brought in contact with acidic aqueous solutions, which have a pH value of 6.0 or less and contain calcium phosphates, whereby a calcium phosphate layer is deposited on the surface of the implant materials. The iron and/or zinc based metal implant materials, which are used in methods according to the invention, are materials consisting of base iron alloys or pure iron or materials that contain other substances, which are coated with pure iron, with a base iron alloy and/or with zinc.

InnoTERE GmbH | Date: 2013-04-11

The invention relates to an implant and a set for producing an implant and their uses. Furthermore, the invention describes a method of making an implant as per the invention. An implant for producing bone implants with improved mechanical characteristics, especially with adjustable mechanical characteristics, is provided via the invention. The implant as per the invention made up of a fiber composite material contains

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