Dual-phase cement precursor systems for rapid bone repair
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Solution Overview
Problem
Existing calcium phosphate cements used for bone repair often have long hardening times, are limited by moisture availability, and have short shelf lives due to moisture sensitivity, which can hinder their utility in clinical bone grafting procedures.
Innovation Solution
A dual-phase cement precursor system comprising two separate phases that combine to form a biocompatible, osteoconductive, and bioresorbable cement, allowing for rapid hardening without the need for water from surrounding tissues, and are stabilized for extended storage and transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional calcium phosphate cements are used for bone repair, then they provide good biocompatibility and osteoconductivity, but they have long hardening times (60 minutes or more) which reduces productivity
Solution Approach 1:
The cement system is divided into two separate phases: a powder phase containing calcium phosphate precursors (TTCP and DCPA) and a liquid phase containing an aqueous solution with setting accelerator. This segmentation allows each phase to be optimized independently - the powder provides structural integrity and biocompatibility while the liquid enables rapid setting through controlled chemical reaction, achieving hardening in 5-30 minutes without compromising biocompatibility
Solution Approach 2:
The invention changes the chemical parameters of the cement system by introducing specific setting accelerators (sodium phosphate, potassium phosphate, or ammonium phosphate) in controlled concentrations (0.1-5% w/w). This parameter modification accelerates the setting reaction kinetics, reducing hardening time from 60+ minutes to 5-30 minutes while maintaining the biocompatible calcium phosphate composition
2Ease of operation
If pre-mixed cement pastes are prepared to eliminate mixing steps, then ease of operation is improved, but the cements become sensitive to moisture which shortens shelf life
Solution Approach 1:
The cement is provided as two separate phases in a ready-to-use kit format - a powder phase and a liquid phase - that remain segregated during storage. This segmentation eliminates the moisture sensitivity problem of pre-mixed pastes while maintaining ease of operation, as the user simply needs to combine the two phases before application. The separated phases can be stored at room temperature with extended shelf life, and mixing occurs only at the moment of use
Solution Approach 2:
The invention performs preliminary preparation by formulating the cement components into stable, pre-measured phases that are ready for immediate use. The powder phase contains pre-mixed calcium phosphate precursors in optimal ratios, and the liquid phase contains the setting accelerator solution at the correct concentration. This preliminary action eliminates the need for complex mixing procedures while preventing premature reaction through phase separation, thus extending shelf life without compromising ease of operation
3Ease of operation
If conventional cements rely on water from surrounding tissues to harden, then they can self-harden in situ, but they are limited by moisture availability which reduces reliability in dry environments
Solution Approach 1:
The cement system carries its own setting accelerator (sodium phosphate, potassium phosphate, or ammonium phosphate) within the liquid phase, making it self-sufficient for the hardening reaction. This eliminates dependency on external moisture from surrounding tissues, as the accelerator provides the necessary chemical environment for rapid setting. The cement can now self-harden reliably in both wet and dry environments, maintaining ease of operation while improving reliability across different moisture conditions
Solution Approach 2:
The invention changes the chemical parameters by incorporating setting accelerators that modify the reaction mechanism. Instead of relying solely on water from tissues to initiate hydroxyapatite formation, the accelerator creates a controlled chemical environment that speeds up and stabilizes the setting reaction. This parameter change enables consistent hardening performance regardless of ambient moisture availability, eliminating the reliability issue while preserving the self-hardening capability
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 dual-phase system enables cements to harden within 90 minutes or less at room temperature, maintaining stability and allowing for efficient bone repair with improved shelf life and reduced moisture sensitivity, enhancing their clinical applicability.
Implementation Method 1
The phases initially are separate, but a cement suitable for bone repair procedures may be formed upon blending of the first and second phases
Implementation Method 2
self-hardens to form hydroxyapatite as the primary product
Data Source
AI summary
Disclosed are dual-phase cement precursor systems and related methods and kits. The cement precursor systems are composed of a first and second discrete phases, at least one of which is aqueous. When combined, the cement precursor phases form a cement that is suitable as a bone graft material for bone repair procedures. In preferred embodiments, the materials are highly biocompatible, osteoinductive, and bioresorbable. A number of different but not mutually exclusive cement chemistries may be employed in the cement precursor systems. For instance, hydrogel-forming polymer cements, carboxyl/calcium cements, or calcium phosphate cements may be employed.