Microstructured Polymeric Coating for Medical Device Friction

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Solution Overview

Problem

Medical devices with tubular bodies experience wear and friction issues due to constant movement, leading to potential failure and short-circuiting, especially when conductive components rub against the inner surface, and rotational atherectomy catheters face lubricant displacement and friction-related failures during curvature.

Innovation Solution

A polymeric coating with microstructures is applied to the inner surface of medical devices, reducing friction and wear by creating a flexible, lubricant-retaining layer that decreases contact surface area and enhances lubrication distribution, thereby protecting the device from abrasion and failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a smooth polymeric coating is applied to reduce friction, then lubrication is improved, but wear protection is reduced due to increased contact surface area

Engineering Contradiction:
ImprovelubricationVSAvoidwear protection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The coating surface is structured with microstructures that create localized regions of different properties: the peaks provide reduced contact area for wear protection, while the valleys provide lubricant retention for reduced friction. This local variation in surface topology simultaneously achieves both wear protection and lubrication.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The polymeric coating incorporates a porous or microstructured surface topology with peaks and valleys. This porous structure allows the coating to retain lubricant within the valleys while presenting a reduced effective contact area through the peaks, thereby achieving both wear protection and sustained lubrication.

Inventive Principle:
Principle #31Porous materials

2Adaptability or versatility

If the lead wire moves constantly to accommodate patient movement, then adaptability is improved, but wear on the inner surface of the lead body increases

Engineering Contradiction:
Improvepatient movement accommodationVSAvoidisolation system durability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The polymeric coating is applied beforehand to the lead wire surface to create a protective barrier against wear. This coating with its microstructured surface provides cushioning and protection before the wear process begins, allowing the lead wire to move freely while protecting the lead body inner surface from abrasion.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If the drive shaft is forced against the catheter during curvature, then catheter flexibility is improved, but lubricant is pushed out and friction increases

Engineering Contradiction:
Improvecatheter flexibilityVSAvoidfriction
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The microstructured surface of the polymeric coating creates localized lubricant reservoirs in the valleys. When the drive shaft contacts the catheter during curvature, these localized lubricant pockets are maintained, preventing complete lubricant displacement and reducing friction even under forced contact conditions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The polymeric coating with its microstructure provides beforehand cushioning by retaining lubricant within the surface structure. This pre-positioned lubricant cushioning prevents direct metal-to-polymer contact and reduces friction before excessive wear or failure can occur during catheter curvature.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 polymeric coating with microstructures effectively reduces wear and friction, maintaining device functionality by minimizing contact surface area and ensuring consistent lubrication, thus preventing short-circuiting and failure in medical devices.

Implementation Method 1

A polymeric coating with microstructures is applied to the inner surface of medical devices, reducing friction and wear by creating a flexible, lubricant-retaining layer that decreases contact surface area and enhances lubrication distribution

Methodology Applied
Scientific EffectFriction reduction: Friction

Implementation Method 2

A polymeric coating with microstructures is applied to the inner surface of medical devices, reducing friction and wear by creating a flexible, lubricant-retaining layer that decreases contact surface area and enhances lubrication distribution

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3346933B1Medical device with a structured coating
Publication Date: 2019.07.10 CARDIAC PACEMAKERS INC
  • EP3346933B1 patent drawingFigure 1
  • EP3346933B1 patent drawingFigure 2
  • EP3346933B1 patent drawingFigure 3

AI summary

A medical device includes a tubular body (202) having a distal end and a proximal end, a lumen (226) extending through the tubular body from the distal end to the proximal end, a wire (220) extending through the lumen from the distal end to the proximal end, and a polymeric coating (232). The wire has an outer surface. The polymeric coating is on at least a portion of the outer surface of the wire. The coating comprises a bulk material and a plurality of flexible microstructures disposed on the bulk material. The microstructures extend outwardly from a surface of the polymeric coating.