Implants for “load bearing” bone substitutions having hierarchical organized architecture deriving from transformation of vegetal structures
Inventors
Tampieri, Anna • Sprio, Simone • Ruffini, Andrea • Will, Julia • Greil, Peter • Muller, Frank • MARTINEZ FERNANDEZ, JULIAN • Torres Raya, Carmen • Varela Feria, Francisco Manuel • Ramirez Rico, Joaquin • Harmand, Marie-Francoise
Assignees
Universidad de Sevilla • LABORATOIRE D?EVALUATION DES MATERIELS IMPLANTABLES • Greenbone Ortho Srl
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Publication Number
US-9326948-B2
Publication Date
2016-05-03
Expiration Date
Abstract
The present invention relates to a bone substitute comprising a core based on hydroxyapatite (HA), obtained from at least one porous wood, or based on collagen fibers and hydroxyapatite, and a shell, based on hydroxyapatite (HA) or silicon carbide (SiC), obtained from at least one wood having a lower porosity than the at least one wood of the core. The porous wood has a total porosity of between 60% and 95%, preferably between 65% and 85%, and it is selected from amongst the choices of rattan, pine, abachi and balsa wood. The wood of the shell has a porosity of between 20% and 60%, preferably between 30% and 50%. The bone substitute is utilized for the substitution and regeneration of bone, preferably for bones subjected to mechanical loads, such as long bones of the leg and arm, preferably the tibia, metatarsus, femur, humerus or radius.
Core Innovation
The disclosed bone substitute comprises a core and a shell where the shell covers at least part of an exterior surface of the core. The core comprises one or more of hydroxyapatite and substituted hydroxyapatite and has a first porosity with a pore structure derived from a first wood such that the pore structure of the core corresponds to a pore structure of the first wood. The first wood is selected from rattan, pine, abachi and balsa wood.
The shell also comprises one or more of hydroxyapatite and substituted hydroxyapatite and has a pore structure derived from a second wood such that the pore structure of the shell corresponds to a pore structure of the second wood. The second wood is selected from sipo, oak, rosewood and kempas, and the second wood has a porosity which is less than the porosity of the first wood. This establishes a hierarchical organized architecture in which the shell porosity is lower than the core porosity while preserving wood-correspondent pore structures.
The shell is coated with a layer comprising collagen mineralized with hydroxyapatite. In one described production approach, the core is produced by pyrolyzing a first wood to yield a carbon material and thereafter transforming the carbon material to yield one or more of hydroxyapatite and substituted hydroxyapatite; the shell is produced similarly from a second wood. In an alternative production approach, the first and second woods are treated and infiltrated with a precursor to yield a precursor material, followed by pyrolyzing and thereafter transforming to yield hydroxyapatite and substituted hydroxyapatite, with the shell coated by the collagen mineralized with hydroxyapatite layer.
Claims Coverage
Two independent claims are present. Together, they define a core-shell bone substitute with wood-correspondent pore structures and hydroxyapatite-based regions, plus a collagen mineralized with hydroxyapatite shell coating; one claim also defines alternative manufacturing pathways for producing core and shell while maintaining the pore-structure correspondence.
Wood-derived core pore structure correspondence with hydroxyapatite
The core comprises one or more of hydroxyapatite and substituted hydroxyapatite, has a first porosity, and has a pore structure derived from a first wood such that the pore structure of the core corresponds to a pore structure of the first wood, the first wood being selected from rattan, pine, abachi and balsa wood.
Wood-derived shell pore structure correspondence with lower wood porosity
The shell comprises one or more of hydroxyapatite and substituted hydroxyapatite, has a pore structure derived from a second wood such that the pore structure of the shell corresponds to a pore structure of the second wood, and the second wood has a porosity which is less than the porosity of the first wood, the second wood being selected from sipo, oak, rosewood and kempas.
Collagen mineralized with hydroxyapatite shell coating
The shell is coated with a layer comprising collagen mineralized with hydroxyapatite.
Core and shell produced via pyrolysis then transformation or via treatment and infiltration then pyrolysis then transformation
The core and shell are produced by either pyrolyzing the respective wood and thereafter transforming the resulting carbon material, or by treating the respective wood, infiltrating it with a precursor, pyrolyzing the precursor material, and thereafter transforming it, while preserving pore-structure correspondence and applying the collagen mineralized with hydroxyapatite coating to the shell.
The claims cover a hierarchical bone substitute with a wood-correspondent porous core and a wood-correspondent porous shell of lower wood porosity, both comprising hydroxyapatite or substituted hydroxyapatite, and a shell surface coated with collagen mineralized with hydroxyapatite.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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