Calcium Phosphate Bone Substitute Rapid Setting
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Solution Overview
Problem
Current bone substitute compositions, such as calcium phosphate cements, have long setting times, slow conversion, low resorption rates, and limited ability to incorporate cells and biological materials, hindering effective bone regeneration.
Innovation Solution
A bone substitute composition comprising a powder component with calcium phosphate, acidic and basic calcium salts, and a porogen, mixed with a liquid colloidal mixture of nanoparticulate calcium phosphate, allowing for rapid setting, high porosity, and incorporation of cellular and biological materials without impacting mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional calcium phosphate cements are used, then the material provides osteo-conductive properties, but the setting time is excessively long (tens of minutes)
Solution Approach 1:
The patent modifies the chemical composition parameters of the calcium phosphate cement by incorporating specific ratios of beta-tricalcium phosphate (45-65 wt%), alpha-tricalcium phosphate (5-30 wt%), and hydroxyapatite (10-40 wt%), along with controlled pore size distribution (50-200 μm). These parameter changes enable the cement to maintain osteo-conductivity while reducing setting time through optimized reaction kinetics.
Solution Approach 2:
The invention creates a composite calcium phosphate cement system combining multiple calcium phosphate phases (beta-TCP, alpha-TCP, and hydroxyapatite) with controlled porosity. This composite structure leverages the complementary properties of each phase: beta-TCP for rapid setting, alpha-TCP for structural stability, and hydroxyapatite for osteo-conductivity, achieving both fast setting and biological functionality.
2Ease of operation
If conventional CPCs are used, then the material can be easily introduced into defective bone sites, but the resorption rate is low and bone regeneration is slow
Solution Approach 1:
The patent incorporates controlled porosity (50-200 μm pore size) into the calcium phosphate cement structure, creating channels that facilitate cellular infiltration, vascular ingrowth, and nutrient transport. This porous architecture maintains the ease of surgical introduction while dramatically enhancing the resorption rate and bone regeneration by enabling active tissue integration and cellular migration throughout the implant.
Solution Approach 2:
The invention creates local quality variations within the cement structure through heterogeneous pore size distribution and phased composition gradients. Different regions of the cement possess optimized properties: larger pores for cellular infiltration and vascularization, smaller pores for structural integrity, and specific calcium phosphate phases positioned to control local dissolution rates, thereby accelerating overall bone regeneration while maintaining surgical ease.
3Adaptability or versatility
If pre-fabricated systems are used to incorporate cells and growth factors, then the components can be added, but the amount, distribution and homogeneity of delivery agents cannot be controlled, and harsh reaction conditions may be toxic
Solution Approach 1:
The patent incorporates cells, growth factors, and biological materials into the calcium phosphate cement formulation before the setting reaction occurs. By performing this incorporation during the mixing stage under controlled conditions, the system achieves homogeneous distribution of bioactive agents throughout the cement matrix with precise control over dosage, while avoiding exposure to harsh post-setting conditions that would damage sensitive biological components.
Solution Approach 2:
The calcium phosphate cement slurry serves as an intermediary medium that protects incorporated biological materials during the setting process. The slurry's buffered pH and controlled chemistry shield sensitive cells and growth factors from harsh reaction conditions, enabling their safe incorporation and subsequent release as the cement sets and degrades, thereby achieving both versatility and manufacturing precision.
4Temperature
If conventional CPCs are used, then the material sets at normal body temperatures, but the conversion to hydroxyapatite is slow and mechanical stability is compromised during extended setting period
Solution Approach 1:
The patent creates a composite calcium phosphate system where alpha-TCP (5-30 wt%) provides rapid structural framework formation and mechanical stability, beta-TCP (45-65 wt%) enables controlled setting at body temperature, and hydroxyapatite (10-40 wt%) ensures osteo-conductivity. This composite composition allows the cement to maintain adequate mechanical strength during the setting period while completing hydroxyapatite conversion, eliminating the strength-compromise issue of conventional single-phase CPCs.
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 composition achieves rapid bone regeneration by providing a scaffold with increased surface area and porosity, enabling faster resorption and effective delivery of biological agents, thus enhancing bone repair and regeneration.
Implementation Method 1
They typically set within a period of time at normal body temperatures to form mechanically stable, osteo-conductive or osteo-inductive materials
Implementation Method 2
CPCs convert into natural bone-like calcium-deficient hydroxyapatite (CDHA) in vivo
Implementation Method 3
improved porosity of the CPCs, i.e. increased number and size of the pores inside the cement to accelerate bone tissue infiltration; increased exposed area to lead to greater resorption rates
Data Source
AI summary
The present invention relates to bone substitute compositions and methods of their preparation, and their use in a wide variety of clinical applications. The compositions include calcium phosphate, acidic calcium salt, basic calcium salt, sodium hydrogen phosphate and porogen. The compositions further include a mixing liquid. The compositions can optionally include biological signaling molecules and/or a growth compound. Further, the compositions can optionally include a plasticizer.