Ionically Modified Polyurethane Medical Articles for Antimicrobial Control
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Solution Overview
Problem
Existing medical devices, such as catheters and syringe cannulas, face issues with infection and thrombosis due to microbial colonization and blood coagulation, and current coating techniques complicate manufacturing and increase costs.
Innovation Solution
A polyurethane-based resin is developed with an anionic modifier, which can be incorporated into the backbone or as a side chain, allowing for inherent antimicrobial and anti-fouling properties or easy bonding of cationic agents, reducing the need for separate surface coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If catheters are impregnated with antimicrobial agents, then antimicrobial efficacy is improved, but the devices lose antifouling efficacy in short time and create regulatory concerns
Solution Approach 1:
The patent modifies the chemical structure of polyurethane by incorporating ionically-charged modifiers (carboxylate or sulfonate groups) into the polymer backbone or side chains. This parameter change in the polymer's chemical composition enables inherent antimicrobial properties through electrostatic repulsion of cationic bacteria, eliminating the need for impregnation and ensuring long-lasting efficacy without leaching issues
Solution Approach 2:
The patent creates a composite polyurethane material combining traditional polyurethane segments with ionically-charged modifier segments. This composite structure integrates the antimicrobial functionality directly into the polymer matrix, achieving both structural integrity and sustained antimicrobial activity without the need for separate impregnation layers
2Reliability
If surface coating techniques are used to bond antimicrobial agents to polymer substrates, then non-leaching properties are improved, but manufacturing process complexity and costs significantly increase
Solution Approach 1:
The patent incorporates ionically-charged modifiers during the initial polymerization process, performing the antimicrobial functionality integration in advance. This preliminary action eliminates the need for subsequent surface coating steps, as the polyurethane itself provides the bonding surface for cationic antimicrobial agents through electrostatic attraction
Solution Approach 2:
The polyurethane with incorporated ionically-charged modifiers serves its own function of providing antimicrobial activity through inherent electrostatic repulsion. The material does not require external coating or treatment to achieve its antimicrobial properties, as the charged groups are an integral part of the polymer structure
3Reliability
If heparin is attached to polymeric surfaces to prevent thrombosis, then anti-fouling properties are improved, but heparin-induced thrombocytopenia regulatory concerns arise
Solution Approach 1:
The patent uses a polyurethane material with inherently stable ionically-charged groups that do not require leachable heparin coating. The antimicrobial and anti-fouling activity is provided by the fixed charged groups in the polymer structure, eliminating the need for heparin attachment and associated regulatory concerns about thrombocytopenia
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 resin provides enhanced antimicrobial and anti-fouling characteristics, simplifies manufacturing, and reduces regulatory concerns and costs by eliminating the need for additional surface treatments.
Implementation Method 1
The ionically-charged modifier is anionic, having at least one functional moiety, which may be, for example, a —SO3− and/or a —COO−
Implementation Method 2
can easily bond cationic active agents to provide desirable material properties, including antimicrobial, anti-fouling, and/or radiopacity
Data Source
AI summary
Medical articles formed from a polyurethane-based resin including an ionically-charged modifier provide enhanced properties. The polyurethane-based resin is a reaction product of ingredients comprising: a diisocyanate; a diol chain extender; a polyglycol; and an anionic modifier incorporated into a backbone, as a side chain, or both of the polyurethane-based resin. Exemplary anionic modifier includes 2,2-bis(hydroxymethyl)butyric acid (BHMBA) and/or bis-1,4-((2-hydroxypropoxy)-2-propoxy)-butane sulfonate sodium salt (SULFADIOL®-7Q). Medical articles herein either have inherent antimicrobial and/or anti-fouling characteristics or can easily bond cationic active agents to provide desirable material properties, including antimicrobial, anti-fouling, and/or radiopacity.