Continuous-fiber reinforced biocomposite medical implants
Inventors
Preiss-Bloom, Orahn • LINDNER, Taly Pnina • EPSTEIN, Eyal • POREH, Danielle
Assignees
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Publication Number
US-10926004-B2
Publication Date
2021-02-23
Expiration Date
Abstract
A medical implant comprising a plurality of biocomposite layers, each layer comprising a polymer and a plurality of uni-directionally aligned continuous reinforcement fibers. The medical implant is suitable for load-bearing orthopedic implant applications and comprises one or more biocomposite materials where sustained mechanical strength and stiffness are critical for proper implant function.
Core Innovation
The invention relates to a medical implant comprising a plurality of biocomposite layers, each layer comprising a polymer and a plurality of continuous reinforcement fibers. The fibers are unidirectionally aligned within each layer, the implant is bioabsorbable, and the polymer is biodegradable. The fiber diameter is 0.1–100 µm, the distance between layers is 0–60 µm, and the density of the biocomposite is 1 to 2 g/mL.
The invention addresses maintaining flexural strength and modulus over extended implantation by controlling fiber alignment and orientation across multiple layers and by defining key fiber and structural parameters. The biocomposite design uses unidirectionally aligned continuous fibers within each layer while orientation may alternate between adjacent layers according to specified angle differences.
The invention further includes embodiments in which the reinforcement fibers are mineral, including bioresorbable glass fibers and silica-based mineral compound fibers having specified oxide mol.% ranges. Structural embodiments include orthopedic implant configurations such as pins, screws, plates, cages, and cannulated designs, including perforations, and embodiments including non-reinforced polymer interface layers and ribs, gussets, or bosses.
Claims Coverage
The partial content identifies one independent claim: clm-00001. The dependent claims refine the independent claim by adding specific constraints on fiber reinforcement, polymer composition and form, fiber orientation alternation between adjacent layers, fiber length fraction, and reinforcement-fiber oxide chemistry.
Multilayer bioabsorbable biocomposite implant with continuous unidirectionally aligned reinforcement fibers
A medical implant comprising a plurality of biocomposite layers, each layer comprising a polymer and a plurality of continuous reinforcement fibers, where fibers are unidirectionally aligned within each layer, the implant is bioabsorbable and the polymer is biodegradable, the fiber diameter is 0.1–100 µm, the distance between layers is 0–60 µm, and the density of the biocomposite is 1 to 2 g/mL.
Fiber reinforcement content constraints by weight and volume
The implant specifies reinforcing fibers having a fiber weight percentage in the range 20–90% or 40–70% and, optionally, a reinforcing-fiber volume percentage in the range 30–90% or 40–70%.
Alternating fiber orientation between adjacent layers
The implant specifies that each layer has directionally oriented fibers with the fiber orientation alternating between adjacent layers at an angle difference of 15–75 degrees, 30–60 degrees, or 40–50 degrees.
Reinforcing fiber length tied to implant longitudinal length
The implant specifies that a reinforcing fiber length for portions or a majority of the fibers is at least 50% of the implant’s longitudinal length, and is set to 60% or 75% of that longitudinal length.
Broad selection of biodegradable polymer forms and classes
The implant specifies that the biodegradable polymer can be a homopolymer or copolymer, including random, block, or graft copolymers, in linear, branched, or dendrimer form, from natural or synthetic origin, and comprising one or more specified biodegradable polymer materials and mixtures or derivatives.
Silica-based mineral compound oxide chemistry for reinforcement fibers
The implant specifies a reinforcing fiber whose silica-based mineral compound contains specified oxide components within mol.% ranges.
In the provided partial content, claim coverage centers on a multilayer bioabsorbable implant with continuous unidirectionally aligned reinforcement fibers, constrained by fiber diameter, interlayer distance, and biocomposite density. The dependent claim refinements further limit fiber content, define how fiber orientation alternates between adjacent layers, constrain reinforcing fiber length relative to implant longitudinal length, expand allowable biodegradable polymer classes and forms, and specify oxide mol.% ranges for silica-based mineral compound reinforcement fibers.
Stated Advantages
Maintains flexural strength and modulus over extended implantation by controlling fiber alignment and orientation and structural parameters while the implant is bioabsorbable and the polymer is biodegradable.
Supports controlled degradation behavior intended to sustain mechanical performance over time during implantation.
Documented Applications
Load-bearing orthopedic medical implant configurations including pins, screws, plates, cages, and cannulated designs, with embodiments including perforations and surface predominance of mineral vs polymer.
Use of simulated body fluid (SBF) and in vitro degradation testing to assess flexural properties and degradation outcomes of the multilayer biocomposite implant with varying fiber content and geometries.
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