Nanofiber Antimicrobial Layer for Implantable Devices
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Solution Overview
Problem
Implantable medical devices are prone to nosocomial infections due to bacterial adhesion on their surfaces, leading to significant costs and patient suffering, as existing solutions fail to effectively prevent such infections.
Innovation Solution
An antimicrobial, antifouling layer is formed on the surfaces of implantable medical devices using nanofibers with a cross-linked poly(ethylene glycol) coating, where the nanofibers are interpenetrated into the polymer substrate and mechanically fixed, projecting a second portion that discourages bacterial adhesion, and the poly(ethylene glycol) is covalently bonded to the nanofibers using argon-containing plasma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional smooth surface is used on implantable medical devices, then the device is easy to manufacture, but bacterial adhesion occurs leading to nosocomial infections
Solution Approach 1:
The patent applies porous nanofiber materials with specific pore sizes (100-1000 nm) that physically prevent bacterial adhesion. The porous structure is created through electrospinning technology, forming a network of interconnected fibers that create a surface topology incompatible with bacterial attachment, thereby preventing infections while maintaining manufacturability through established electrospinning processes
Solution Approach 2:
The patent creates composite materials by combining nanofibers with polymer substrates (e.g., silicone, polyurethane). The nanofiber layer is integrated with the base polymer to form a composite surface that retains the mechanical properties of the polymer while adding antimicrobial functionality through the nanofiber structure, achieving both infection prevention and ease of manufacture
2Reliability
If an antimicrobial coating is applied to device surfaces, then bacterial colonization is reduced, but the coating may detach over time reducing durability
Solution Approach 1:
The patent merges the nanofiber layer with the polymer substrate through mechanical interpenetration and chemical bonding. The nanofibers are embedded into the polymer matrix during the molding process, creating a unified structure where the antimicrobial nanofiber surface is permanently integrated with the device substrate, eliminating detachment issues while maintaining long-term antimicrobial effectiveness
Solution Approach 2:
The patent uses silane coupling agents as intermediaries to chemically bond the nanofiber surface to the polymer substrate. The silane molecules form covalent bonds with both the nanofiber material and the polymer, creating a strong chemical bridge that ensures permanent attachment and prevents coating detachment over time, thereby ensuring both antimicrobial effectiveness and durability
3Duration of action of stationary object
If nanofibers are mechanically fixed to the substrate, then the antimicrobial layer is durable, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by pre-coating nanofibers with silane coupling agents before integration with the polymer substrate. This pre-treatment prepares the nanofiber surface for optimal chemical bonding, ensuring durable attachment while simplifying the overall manufacturing process by separating the surface treatment step from the integration step, making the process more controllable and less complex
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 antimicrobial layer significantly reduces bacterial colonization on the device surfaces, providing a durable and effective barrier against infections, thereby minimizing the occurrence of nosocomial infections and associated costs and patient distress.
Implementation Method 1
interpenetrating a first portion of at least one nanofiber within a surface portion of the substrate, the surface portion extending from the surface into the substrate, the surface portion being in a liquid or semi-liquid state; and solidifying the surface portion, wherein the first portion of the at least one nanofiber is mechanically fixed within the surface portion
Implementation Method 2
the poly(ethylene glycol) is covalently bonded to the nanofibers using argon-containing plasma
Implementation Method 3
the poly(ethylene glycol) is covalently bonded to the nanofibers
Implementation Method 4
a cross-linked poly(ethylene glycol) coating mechanically linked to the second portion of the at least one nanofiber
Data Source
AI summary
An implantable medical device includes a polymer substrate and at least one nanofiber. The polymer substrate includes a surface portion extending into the polymer substrate from a surface of the substrate. The at least one nanofiber includes a first portion and a second portion. The first portion is interpenetrated with the surface portion of the substrate, and mechanically fixed to the substrate. The second portion projects from the surface of the substrate.