Alkaline Earth Phosphate Bone Cement with Chitosan Polymer
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Solution Overview
Problem
Conventional bone cements, such as PMMA-based cements, face issues like tissue irritation, exothermic polymerization, and poor biocompatibility, while alternative alkaline earth phosphate cements struggle with reproducibility and injectability due to the need for mixing two solid powders, which affects their clinical usability and effectiveness in surgical applications.
Innovation Solution
A bone cement composition using a single powder component, such as calcium, magnesium, or strontium, mixed with a setting solution containing phosphoric acid and a biocompatible polymer like chitosan, which can be irradiated to form dry powders for improved handling and reduced exothermicity, allowing for enhanced mechanical properties and biocompatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If PMMA-based cements are used, then bone cement strength is achieved, but tissue irritation and exothermic polymerization damage surrounding tissue
Solution Approach 1:
The patent changes the chemical composition parameters from PMMA-based to alkaline earth phosphate-based cements (calcium, magnesium, or strontium phosphates), which fundamentally alters the setting reaction from exothermic polymerization to acid-base reaction, thereby reducing tissue irritation and exothermic damage while maintaining bone cement strength
Solution Approach 2:
The patent creates composite bone cement materials by combining alkaline earth phosphate powders with specific setting solutions containing polymers and other additives, forming a composite system that achieves both mechanical strength and biocompatibility
2Quantity of substance
If two solid powder ingredients are mixed, then cement composition is achieved, but batch-to-batch reproducibility and shelf life are reduced
Solution Approach 1:
The patent segments the cement system into distinct powder and liquid components that are mixed only at the time of use, allowing each component to be stored separately under optimal conditions independently, thereby maintaining shelf life and ensuring consistent composition through controlled mixing ratios
Solution Approach 2:
The patent performs preliminary preparation of stable powder and liquid components separately, with the powder component being pre-synthesized and characterized for consistent composition, and the liquid component being pre-formulated with stabilizers, ensuring that when mixed, they produce reproducible results across batches
3Quantity of substance
If two solid ingredients are mixed, then cement formulation is achieved, but homogeneous mixing is difficult and injectability is poor
Solution Approach 1:
The patent employs a liquid setting solution that flows readily to facilitate homogeneous mixing with the powder component, and the resulting cement paste maintains appropriate rheological properties for injectability through minimally invasive procedures, utilizing fluid dynamics principles to achieve uniform distribution
Solution Approach 2:
The patent optimizes the liquid-to-powder ratio and viscosity parameters of the setting solution to achieve optimal flow characteristics for easy mixing and injection, while maintaining sufficient cohesion to prevent washout during the setting process
4Ease of operation
If polymer is incorporated in setting solution, then injectability and cohesiveness are enhanced, but mixing complexity increases
Solution Approach 1:
The patent incorporates the polymer component within the setting solution matrix, nesting multiple functional elements (polymer for cohesiveness, acid-base reactants for setting, additives for performance) within a single liquid phase that mixes uniformly with the powder component, thereby achieving enhanced injectability without proportionally increasing mixing complexity
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 solution provides a bone cement with improved strength, bioactivity, and reduced exothermicity, enabling effective use in surgical applications, including weight-bearing scenarios, with enhanced injectability and biocompatibility, addressing the limitations of existing cements.
Implementation Method 1
The powder component comprises a basic source of calcium, magnesium, or strontium. The setting solution comprises phosphoric acid. Upon mixing, a paste forms that either (a) hardens into a solid mass some period of time after mixing the powder with the setting solution
Implementation Method 2
A method comprises mixing one powder component with a setting solution and a biocompatible polymer to form a paste, then allowing the paste to set into a hardened mass. Another method comprises forming a bone cement paste from an acid-base reaction, irradiating the bone cement paste with electromagnetic radiation to form dry powders
Data Source
AI summary
Compositions of, methods of making, and methods of using alkaline earth phosphate bone cements are disclosed. A bone cement composition includes a powder comprising a basic source of calcium, magnesium, or strontium, a setting solution comprising H3PO4 and a buffer, and a biocompatible polymer that is incorporated into the setting solution. The powder is mixed with the setting solution to form a bone cement paste that either (a) sets into a hardened mass, or (b) is irradiated with electromagnetic radiation to form dry powders, the dry powders then being mixed with a second setting solution to form a radiation-assisted bone cement paste that sets into a hardened mass.