Adhesive Complex Coacervates for Bone Fracture Fixation
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Solution Overview
Problem
Current methods for fixing bone fractures, particularly comminuted injuries of the articular surface and metaphysis, face challenges due to the limitations of titanium and stainless steel implants, including interference with precise manipulation and reduction, and the drawbacks of existing bone adhesives such as PMMA cements and fibrin glues, which can cause tissue damage and have supply limitations.
Innovation Solution
Development of polymers that form adhesive complex coacervates through crosslinking of polyanions and polycations, which can be used to create strong bonds with bone tissue, facilitating the maintenance of fracture reduction and potentially reducing the risk of posttraumatic arthritis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If titanium or stainless steel implants are used for fixation, then fracture stability is improved, but manipulation precision and reduction accuracy are worsened due to implant size and drilling requirements
Solution Approach 1:
The patent replaces mechanical fixation systems (screws, plates, and implants requiring drilling) with a chemical bonding system using polymers and adhesives. This substitution eliminates the need for large implants and drilling operations, thereby improving manipulation precision and reduction accuracy while maintaining fracture stability through chemical adhesion to bone surfaces.
2Strength
If PMMA cements are used for fixation, then bonding strength is improved, but tissue viability is worsened due to exothermic heat generation
Solution Approach 1:
The patent changes the thermal parameters of the cementing process by using polymers and adhesives with low or zero exothermic reaction characteristics. This eliminates the harmful heat generation that damages bone tissue while maintaining adequate bonding strength through alternative chemical bonding mechanisms that do not rely on high-temperature curing.
Solution Approach 2:
The patent employs biodegradable polymers and adhesives that provide temporary bonding strength during the healing process and then degrade harmlessly. These materials replace permanent, high-strength cements like PMMA with shorter-lived, biocompatible materials that maintain tissue viability while providing sufficient fixation during bone healing.
3Reliability
If fibrin glues are used for fixation, then biocompatibility is improved, but supply reliability is worsened due to limited donor blood availability
Solution Approach 1:
The patent creates synthetic or recombinant versions of naturally occurring biocompatible bonding materials. Instead of relying on pooled human donor blood for fibrin glue, the invention uses synthesized polymers or recombinant proteins that replicate the desirable biocompatibility properties while eliminating supply limitations associated with donor blood availability.
4Reliability
If CP cements are used for fixation, then biocompatibility is improved, but mechanical strength is worsened due to brittleness
Solution Approach 1:
The patent develops composite materials that combine the biocompatibility of calcium phosphate components with the mechanical strength of polymer matrices. These composite adhesives and polymers integrate the osteoconductivity and biocompatibility of CP with the toughness and flexibility of organic polymers, achieving both high biocompatibility and adequate mechanical strength for fracture fixation.
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 polymers enable effective adhesion to bone and other minerals, allowing for less invasive surgery, reducing operating time and costs, and improving fracture stability, while minimizing interference with healing and avoiding the limitations of existing fixation methods.
Implementation Method 1
The polycations and polyanions are crosslinked with one another by covalent bonds upon curing
Implementation Method 2
The polymers enable effective adhesion to bone and other minerals
Data Source
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AI summary
Described herein is the synthesis of adhesive complex coacervates. The adhesive complex coacervates are composed of a mixture of one or more polycations, one or more polyanions, and one of more multivalent cations. The polycations and polyanions in the adhesice complex coacervate are crosslinked with one another by covalent bonds upon curing. The adhesive complex coacervates have several desirable features when compared to conventional bioadhesives, which are effective in water-based applicatgions. The adhesive complex coacervates described herein exhibit good interfacial tension in water when applied to a substrate (i.e., they spread over the interface rather than being beaded up). Additionally, the ability of the complex coacervate to crosslink intermolecularly increases the cohesive strength of the adhesive complex coacervate. The adhesive complex coacervates have numerous biological applications as bioadhesives and drug delivery devices. In particular, the adhesive complex coacervates described herein are particularly useful in underwater applications and situations where water is present such as, for example, physiological conditions.