Fiber Bundle Biocomposite Implants for Sustained Bone-Matched Stiffness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current medical implants, both metallic and biodegradable, face challenges in load-bearing applications due to insufficient mechanical strength and stiffness, leading to complications such as bone remodeling, stress shielding, and premature failure, while biodegradable composites fail to maintain mechanical properties over the required healing period.
Innovation Solution
A biocomposite material comprising fiber bundles aligned along an axis, embedded in a biodegradable polymer, providing sustained mechanical strength and stiffness equivalent to cortical bone for extended periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal alloys (stainless steel or titanium) are used for load-bearing orthopedic implants, then high strength and stiffness are achieved, but stress shielding and bone remodeling occur due to mismatched mechanical properties compared to cortical bone
Solution Approach 1:
The patent employs composite materials consisting of biodegradable polymer matrix reinforced with high-strength fibers (carbon fiber, glass fiber, or aromatic polyamide fiber). This composite structure achieves high strength and stiffness comparable to metal implants while maintaining biodegradability, thereby preventing stress shielding and bone remodeling issues associated with permanent metal implants.
Solution Approach 2:
The patent utilizes fibers with specific mechanical properties (tensile strength ≥1000 MPa, modulus ≥50 GPa) and controlled fiber orientation (0° to 30° relative to implant longitudinal axis) to tune the composite's mechanical properties. By adjusting fiber content (20-80 wt%), orientation, and type, the implant's strength and stiffness can be matched to cortical bone, preventing stress shielding while maintaining load-bearing capacity.
2Duration of action of stationary object
If non-reinforced resorbable polymers are used for medical implants, then eventual resorption eliminating need for removal surgery is achieved, but mechanical strength and modulus are insufficient to support fractured cortical bone
Solution Approach 1:
The patent creates a composite material system where biodegradable polymer matrix (providing resorbability) is reinforced with high-strength fibers (providing mechanical support). The fiber-reinforced composite achieves tensile strength ≥100 MPa and modulus ≥3 GPa, sufficient to support cortical bone, while the polymer matrix ensures eventual resorption and elimination of removal surgery.
Solution Approach 2:
The patent segments the implant material into two functional components: biodegradable polymer matrix that provides resorbability and degradation products clearance, and reinforcing fibers that provide mechanical strength. This segmentation allows each component to fulfill its specific function optimally while working together as a unified implant system.
3Strength
If biodegradable composites with glass fibers are used to improve stiffness and strength, then initial mechanical properties are enhanced, but strength and stiffness become lower than cortical bone following rapid degradation in physiological environment
Solution Approach 1:
The patent carefully selects and controls degradation parameters including polymer matrix composition (PLA, PGA, PLGA, PCL), fiber type (carbon, glass, aromatic polyamide), fiber content (20-80 wt%), and fiber orientation (0° to 30°). These parameter optimizations ensure the implant maintains strength and stiffness equivalent to or greater than cortical bone for the required duration, preventing premature failure while allowing controlled resorption.
Solution Approach 2:
The patent accelerates the development of composite materials with optimized degradation rates by selecting specific polymer-fiber combinations and processing conditions that achieve target mechanical properties and degradation profiles more rapidly, allowing the implant to maintain sufficient strength throughout the bone healing period before controlled resorption occurs.
4Strength
If fiber bundles with high alignment (0 to 5 degrees) are used, then mechanical strength and stiffness are maximized, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the fiber alignment angle parameter, specifying 0° to 5° relative to the bundle axis and 0° to 30° relative to the implant longitudinal axis. This parameter optimization balances mechanical performance (maximizing strength and stiffness) with manufacturing feasibility, avoiding excessively tight tolerances while achieving cortical bone-equivalent mechanical properties.
Solution Approach 2:
The patent applies different fiber bundle orientations strategically: primary load-bearing regions utilize highly aligned bundles (0° to 5°) for maximum strength, while other regions may use bundles at 0° to 30° to accommodate manufacturing constraints and distribute loads appropriately. This local quality approach optimizes mechanical performance where critical while maintaining manufacturing practicality elsewhere.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A medical implant comprising a plurality of fiber bundles, each bundle comprising a polymer and a plurality of uni-directionally aligned continuous reinforcement fibers.