Magnesium Phosphate Bone Cement Porous Gel Layer
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Solution Overview
Problem
Current bone cements, such as calcium phosphate and PMMA, face issues with slow degradation, inflammatory reactions, and inadequate biocompatibility, which hinder fracture healing and cause adverse tissue effects due to ion imbalances during degradation.
Innovation Solution
A magnesium phosphate bone cement is developed with a silicon-containing compound to form a porous gel layer that enhances protein adsorption and biocompatibility, and adjustable porosity to match bone growth rates, using specific ratios of phosphate and ammonium dihydrogen phosphate to control degradation and add degradable adhesion-promoting materials like sugars and beeswax for improved cohesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If calcium phosphate is used as bone cement, then biocompatibility is improved, but degradation rate becomes too slow
Solution Approach 1:
The patent uses composite materials by combining magnesium phosphate with calcium phosphate and other additives to create a bone cement that maintains biocompatibility while achieving faster degradation. The magnesium phosphate component provides controlled degradation rate, while calcium phosphate ensures osteoconductivity and biocompatibility.
Solution Approach 2:
The patent changes the chemical composition parameters by using magnesium phosphate instead of traditional calcium phosphate as the primary component, and by adjusting the ratio of calcium to phosphorus. This parameter change enables faster degradation while maintaining biocompatibility through the specific chemical properties of magnesium phosphate.
2Ease of manufacture
If PMMA bone cement is used, then formability and cohesiveness are improved, but heat release causes tissue necrosis
Solution Approach 1:
The patent utilizes phase transitions by designing a bone cement that sets through a chemical reaction at body temperature rather than requiring high-temperature polymerization. The magnesium phosphate-based cement sets at physiological temperatures, avoiding the exothermic heat release that causes tissue necrosis in PMMA materials.
Solution Approach 2:
The patent employs degradable materials that are temporarily present in the body to provide structural support during healing, then naturally degrade and are absorbed. This replaces the permanent PMMA material with a temporary, biocompatible solution that eliminates long-term heat-related complications.
3Strength
If PMMA bone cement is used, then cohesiveness is improved, but shrinkage during solidification occurs
Solution Approach 1:
The patent changes the solidification mechanism from polymerization shrinkage (PMMA) to chemical setting through precipitation and crystallization of magnesium phosphate. This parameter change in the setting reaction eliminates volumetric shrinkage while maintaining adequate cohesiveness through the interlocking crystalline structure.
4Ease of manufacture
If PMMA bone cement is used, then formability is improved, but biocompatibility deteriorates due to non-degradability
Solution Approach 1:
The patent creates a composite material system combining magnesium phosphate (degradable, biocompatible) with additives that provide formability. This composite approach allows the material to be molded and injected like PMMA while being fully degradable and biocompatible, eliminating the trade-off between formability and biocompatibility.
5Strength
If existing bone cement is used for adhesion, then connection strength is achieved, but degradation rate does not match bone healing rate
Solution Approach 1:
The patent applies dynamics by designing a bone cement with time-dependent properties that evolve during the healing process. The material maintains high strength initially to provide stable fixation, then progressively degrades at a controlled rate that matches bone regeneration, transitioning from a load-bearing implant to a fully integrated biological structure.
Solution Approach 2:
The patent changes the degradation parameter by using magnesium phosphate, which degrades faster than calcium phosphate but controllable through composition adjustments. This enables the degradation rate to be tuned to match the bone healing rate while maintaining adequate connection strength throughout the healing process.
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 magnesium phosphate bone cement promotes extracellular response, reduces ion toxicity, enhances adhesive force, and matches bone growth rates, maintaining strength and biocompatibility, facilitating bone repair and fixation without adverse reactions.
Implementation Method 1
a silicon-containing compound is added to the magnesium phosphate bone cement of the present invention. In the process of degradation, a porous gel layer rich in Si-O-Si is generated on the surface of the bone cement
Implementation Method 2
the degradation of potassium salt-typed MPC in body will cause the abnormal increase of ions (such as potassium ions and magnesium ions) in local body fluids
Data Source
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AI summary
A magnesium phosphate bone cement includes a powder agent and a liquid agent. A liquid-to-solid ratio of the liquid agent to the powder agent is 0.1-0.5 ml/g. The powder agent comprises following components: phosphate accounting for 32-70 wt%, magnesium oxide accounting for 28-65 wt%, and silicon-containing compound accounting for 1-15 wt%. Preferably, the powder agent further comprises ammonium dihydrogen phosphate, and degradable and adhesion-promoting material, wherein the ammonium dihydrogen phosphate accounts for 5-30 wt% of a total weight of the phosphate.