Stent Surface Carbon Layer for Polymer-Free Drug Coating

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Solution Overview

Problem

Existing medical devices coated with polymer layers for bioactive agents face issues such as inflammation, thrombotic responses, and inconsistent drug dosing, leading to regulatory compliance challenges and reduced device performance.

Innovation Solution

A method involving the removal of non-volatile carbon deposits from medical device surfaces, followed by a controlled application of a carbon layer, and then a bioactive material layer, ensuring a uniform and reliable coating without polymer or containment matrices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polymer layer is used to contain and control release of bioactive agent, then drug dosing and adherence are improved, but inflammation, thrombotic response, and neointimal proliferative response are caused

Engineering Contradiction:

Improvedrug dosing consistencyVSAvoidinflammation and thrombotic response

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the polymer containment layer from the medical device coating system. Instead of using a polymer matrix to hold and release the drug, the invention applies the bioactive agent directly to the device surface, eliminating the source of inflammation and thrombotic responses while maintaining drug delivery functionality through direct surface coating

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary coating layer between the metal device and the bioactive agent. This intermediate layer serves as a bonding interface that enhances drug adherence to the device surface without requiring a polymer containment matrix, thus avoiding the harmful effects of polymers while ensuring reliable drug dosing

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If no polymer containment layer is used, then inflammation and thrombotic response are reduced, but reliable and uniform coating of bioactive agent becomes problematic

Engineering Contradiction:

Improvethrombotic responseVSAvoidcoating uniformity

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies preliminary surface treatment and preparation steps before coating the bioactive agent. This includes cleaning, activating, or modifying the device surface in advance to create optimal conditions for uniform drug adhesion, ensuring consistent coating quality without relying on polymer containment layers

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent modifies surface parameters such as surface energy, roughness, or chemical composition to enhance bioactive agent adherence. By changing these surface parameters through treatment processes, the invention achieves reliable and uniform drug coating directly on the device surface without polymer intermediaries

Inventive Principle:

Principle #35Parameter changes

3Reliability

If polymer coating is applied to ensure adequate drug adherence, then dosing consistency is achieved, but device complexity and manufacturing process complexity increase

Engineering Contradiction:

Improvedrug adherenceVSAvoidcoating structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the complex polymer containment structure from the coating system, simplifying the overall device architecture. By eliminating the polymer layer while implementing direct surface coating techniques, the invention reduces structural complexity while maintaining adequate drug adherence through improved surface preparation and application methods

Inventive Principle:

Principle #2Taking out (Extraction)

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

This approach results in improved bioactive agent adhesion, increased drug loading, and reduced variability in coating uniformity across devices, enhancing both the reliability and consistency of drug delivery while minimizing adverse reactions.

Implementation Method 1

applying a layer of carbon over the at least one surface by a carbon deposition process

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 2

applying a layer of bioactive material over the layer of carbon

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Data Source

PatentUS20240024543A1Regulation/modification of stent contact surface for polymer free drug coating

Publication Date: 2024.01.25 COOK MEDICAL TECHNOLOGIES LLC

AI summary

There is disclosed a method of improving the reliability of coating an implantable medical device, such as a stent, with bioactive material in the absence of a carrier material such as a matrix or polymer layer. The method involves cleaning volatile components from the exposed surfaces of the medical device, removing carbon deposits and then applying a uniform carbon layer in a controlled environment. The deliberately applied carbon layer masks impurities of the underlying native oxide layer and leads to more uniform bioactive material coating not only a over the surfaces of a single medical device but also from device to device within a batch and between batches of devices. This improves production as well as optimising the amount and release of drug on the medical device without the need for a carrier material.