Biodegradable Bone Cement With Surface-Eroding PMAA Polymers
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Solution Overview
Problem
Conventional PMMA-based bone cements suffer from non-biocompatibility, non-biodegradability, and tissue adverse effects, such as toxicity and necrosis, limiting their use in orthopedic and dental applications.
Innovation Solution
Development of biodegradable polymers, specifically cyclic poly(methacrylic anhydride) (PMAA) cyclopolymers, which undergo surface erosion and hydrolytic bond cleavage, providing mechanical strength and degrading into water-soluble, non-toxic acid end-products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional PMMA-based bone cement is used, then mechanical strength and structural stability are provided, but biocompatibility and biodegradability deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters by replacing PMMA with cyclic polyanhydride polymers having specific molecular weights (1,000-1,000,000 g/mol) and cyclic structures. This parameter change enables the material to maintain mechanical strength while improving biocompatibility and biodegradability, as the cyclic structure degrades into non-toxic monomers through hydrolysis.
Solution Approach 2:
The patent creates a composite cement system combining cyclic polyanhydride polymer with monomers, initiators, and optional fillers. This composite approach allows the material to achieve both mechanical strength from the polymer matrix and controlled degradation through the cyclic structure, while the composite formulation can be optimized for specific applications to balance strength and biodegradability.
2Stability of the object's composition
If conventional PMMA-based bone cement is used, then structural stability is maintained, but biodegradability deteriorates
Solution Approach 1:
The patent introduces dynamic degradation behavior where the cyclic polyanhydride structure transitions from a stable, load-bearing state to a degrading state over time. The material provides structural stability during the healing period and then progressively degrades through hydrolysis of the cyclic bonds, allowing the body to naturally absorb the material. This dynamic behavior is controlled by the polymer's molecular weight and cyclic structure.
Solution Approach 2:
The patent utilizes parameter changes in the polymer's molecular weight (1,000-1,000,000 g/mol) and cyclic structure to control the degradation timeline. By selecting appropriate molecular weights and cyclic configurations, the material maintains structural stability during the critical healing phase and then degrades at a controlled rate, transforming from a permanent implant to a biodegradable system.
3Object-affected harmful factors
If biodegradable bone cement is developed, then tissue adverse effects are reduced, but mechanical strength deteriorates
Solution Approach 1:
The patent develops a composite material system where cyclic polyanhydride polymer is combined with appropriate monomers, initiators, and potential reinforcement fillers. This composite formulation enables the material to achieve sufficient mechanical strength for bone cement applications while maintaining biodegradability, as the cyclic structure can be designed to degrade into non-toxic monomers that are metabolized by the body.
Solution Approach 2:
The patent optimizes parameters including polymer molecular weight (1,000-1,000,000 g/mol), cyclic structure configuration, and composition ratios to balance mechanical strength with biodegradability. By carefully controlling these parameters, the material provides adequate strength during the healing period and then degrades safely, avoiding tissue adverse effects while maintaining structural integrity when needed.
4Duration of action of stationary object
If surface erosion degradation mechanism is used, then controlled degradation is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent achieves controlled surface erosion degradation by changing the polymer's molecular parameters, specifically using cyclic polyanhydride structures with controlled molecular weights (1,000-1,000,000 g/mol). This parameter-based control allows the material to degrade in a predictable, surface-erosion manner without requiring complex manufacturing processes or additional control mechanisms, as the degradation behavior is inherent in the polymer's molecular structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The PMAA cyclopolymers offer controlled degradation, maintaining mechanical stability and promoting bone ingrowth, eliminating the need for surgical removal and reducing tissue adverse effects.
Implementation Method 1
Bone cement formulations using methacrylic anhydride cyclopolymers according to the present invention undergo hydrolytic bond cleavage, which leads to water soluble and nontoxic acid end-products
Implementation Method 2
the present invention further provides bone cement by utilizing surface-eroding PMAA cyclopolymers to provide bone-like mechanical strength throughout the degradation process
Implementation Method 3
Bone cement is inserted in the body, usually to join natural or artificial bone portions, and is cured (hardened) by polymerization of the monomer
Data Source
AI summary
A class of biodegradable, surface-eroding cyclic poly(methacrylic anhydride) (PMAA) polymer-based biomaterials that are useful as bone cement or bio-adhesives. The synthesis of the biomaterials involves the preparation of linear cyclic PMAA prepolymers. The biomaterials may be further processed to make bone cement for orthopedic applications. Extensive testing of the biomaterials has confirmed that they are biodegradable, have a peak exotherm that is below 45° C., have no or negligible shrinkage, and have good mechanical properties. The biomaterials therefore provide advantages over commercial poly(methyl methacrylate) (PMMA) based bone cements that are currently used in medical applications ranging from dentistry to orthopedics.