Porous composite biomaterials and related methods
Inventors
Roeder, Ryan K • Converse, Gabriel L • Smith, Stephen M
Assignees
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Publication Number
US-10945854-B2
Publication Date
2021-03-16
Expiration Date
Abstract
Synthetic composite materials for use, for example, as orthopedic implants are described herein. In one example, a composite material for use as a scaffold includes a thermoplastic polymer forming a porous matrix that has continuous porosity and a plurality of pores. The porosity and the size of the pores are selectively formed during synthesis of the composite material. The example composite material also includes a plurality of a anisometric calcium phosphate particles integrally formed, embedded in, or exposed on a surface of the porous matrix. The calcium phosphate particles provide one or more of reinforcement, bioactivity, or bioresorption.
Core Innovation
The invention relates to a porous reinforced composite scaffold material comprising a polyaryletherketone polymer and a plurality of anisometric reinforcement particles comprising calcium phosphate crystals distributed essentially uniformly throughout the polyaryletherketone polymer. The anisometric reinforcement particles are embedded within the polyaryletherketone polymer and exposed on struts within pore voids, and are present from about 1 to about 60%, by volume, in the polyaryletherketone polymer.
The scaffold material comprises a substantially continuously interconnected plurality of pores that are uniformly distributed throughout the polyaryletherketone polymer. The pores are defined by voids interconnected by struts, with pore sizes within the range from about 10 to 500 µm. The pore network design yields a porous reinforced composite scaffold material with a compressive elastic modulus similar to that of trabecular bone.
The scaffold is formed by mixing particles of the polymer, reinforcement particles, and particles of a porogen within a fluid to obtain a substantially uniform mixture, removing the fluid, molding the particle mixture at a temperature from between 20 to 400 degrees C., and removing the porogen particles. The partial content also includes functionally graded porosity and optional inclusion of a Bone Morphogenetic Protein (BMP).
Claims Coverage
The document includes two independent claims. The claims share the core structure of a polyaryletherketone porous composite with essentially uniformly distributed anisometric calcium phosphate reinforcement particles and a substantially continuously interconnected pore network with specified pore size and reinforcement volume fraction, and one independent claim adds a modulus-to-trabecular-bone similarity requirement and a strut-embedded/extend feature.
Uniformly distributed anisometric calcium phosphate reinforcement in a polyaryletherketone polymer
A plurality of anisometric reinforcement particles comprising calcium phosphate crystals distributed essentially uniformly throughout the polyaryletherketone polymer.
Substantially continuously interconnected uniformly distributed pore network
A substantially continuously interconnected plurality of pores that are uniformly distributed throughout the polyaryletherketone polymer, where the pores are defined by voids interconnected by struts.
Anisometric reinforcement particles embedded in and exposed on struts within pore voids
Anisometric reinforcement particles are both embedded within the polyaryletherketone polymer and exposed on the struts within the pore voids.
Specified pore size and reinforcement volume fraction
Pores have a size within the range from about 10 to 500 µm, and anisometric reinforcement particles are present from about 1 to about 60%, by volume, in the polyaryletherketone polymer.
Porogen-based mixing, molding, and porogen removal scaffold formation
Mixing particles of the polymer, reinforcement particles, and particles of a porogen within a fluid to obtain a substantially uniform mixture; removing the fluid; molding the particle mixture at a temperature from between 20 to 400 degrees C.; and removing the porogen particles.
Strut-surface embedding with extension into pore voids
At least a portion of the plurality of anisometric reinforcement particles are embedded in and extend from a strut surface into a pore void.
Compressive elastic modulus similar to trabecular bone
The porous reinforced composite scaffold material has a compressive elastic modulus similar to that of trabecular bone.
Across the independent claims, the inventive concept centers on a polyaryletherketone scaffold with a substantially continuously interconnected and uniformly distributed pore network and essentially uniformly distributed anisometric calcium phosphate reinforcement particles that are embedded and exposed or extending from struts into pore voids. The scaffold is produced via mixing with a porogen, molding at 20 to 400 degrees C., and removing the porogen, with one independent claim further requiring a compressive elastic modulus similar to trabecular bone.
Stated Advantages
A compressive elastic modulus similar to that of trabecular bone.
Documented Applications
Orthopedic scaffolds/implants, including interbody spinal fusion cages.
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