Low Molecular Weight Dextran Sulfate Stabilized Enzyme Medical Devices
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Solution Overview
Problem
Implantable medical devices, such as tunneled catheters, face challenges with fibrin sheath formation and thrombosis, leading to reduced functionality and complications like postphlebitic syndrome and pulmonary embolism, as existing stabilization methods for fibrinolytic enzymes are ineffective for long-term use.
Innovation Solution
A medical device with a polyurethane base material immobilized with urokinase-type plasminogen activator (uPA) and low molecular weight dextran sulfate, combined with chlorhexidine, which stabilizes the enzyme and reduces microbial growth, providing extended thrombolytic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional stabilization agents are used to stabilize fibrinolytic enzymes in solution, then enzyme stability is improved, but the duration of thrombolytic activity on implantable medical devices remains insufficient (less than two weeks)
Solution Approach 1:
The patent changes the molecular weight parameter of dextran sulfate from conventional high molecular weight to low molecular weight (less than 40 kDa), which fundamentally alters the stabilization mechanism and extends enzyme activity duration from less than two weeks to at least 28 days on implantable medical devices
Solution Approach 2:
The patent creates a composite coating system combining low molecular weight dextran sulfate with fibrinolytic enzymes (such as urokinase) on the surface of implantable medical devices, forming a stabilized enzyme complex that maintains prolonged thrombolytic activity
2Reliability
If fibrinolytic enzymes are immobilized on implantable medical devices to prevent thrombosis, then thrombosis risk is reduced, but the functional activity is lost within two weeks
Solution Approach 1:
The patent modifies the molecular weight parameter of the stabilizing agent (dextran sulfate) to low molecular weight (less than 40 kDa), which enables the immobilized fibrinolytic enzymes to maintain functional activity for at least 28 days on implantable medical devices, extending the effective duration from less than two weeks to 28 days or longer
Solution Approach 2:
The patent introduces low molecular weight dextran sulfate as an intermediary substance that mediates between the immobilized fibrinolytic enzyme and the device surface, protecting the enzyme and extending its functional lifespan while maintaining thrombosis prevention 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 combination of uPA with low molecular weight dextran sulfate and chlorhexidine significantly extends the duration of fibrinolytic activity on medical devices, maintaining up to 80% activity for 28 days and reducing microbial adherence, thereby enhancing the device's performance and safety.
Implementation Method 1
The low molecular weight dextran sulfate stabilizes the fibrinolytic enzyme
Implementation Method 2
The chlorhexidine base and/or a pharmaceutically acceptable salt thereof is disposed in the polyurethane base material in an amount sufficient to reduce microbial growth
Implementation Method 3
The fibrinolytic enzyme is sufficient to reduce the formation of blood clots in a patient
Data Source
AI summary
A medical device includes a base material having an immobilized fibrinolytic enzyme and dextran sulfate. The dextran sulfate has a molecular weight that is less than 40 kilo dalton (kDa). The medical device is formed from at least a base material. A fibrinolytic enzyme is immobilized on the base material. The fibrinolytic enzyme is stabilized with a dextran sulfate having a molecular weight of less than 40 (kDa).