Antithrombogenic Copolymer Coating for Medical Devices
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Solution Overview
Problem
Medical devices with surface steps prone to thrombus formation due to impaired blood flow and insufficient antithrombogenicity in existing materials, particularly under severe conditions.
Innovation Solution
A medical device with a coating layer containing a copolymer comprising specific repeating units (A) and (B), where unit (A) is present in a proportion of 1 to 7 mol % to enhance antithrombogenicity while controlling water solubility, preventing material elution and thrombus formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a medical device has steps on the surface that contacts blood, then the device structure is necessary for functionality, but blood flow is impaired at the steps resulting in thrombus formation
Solution Approach 1:
The patent introduces an antithrombogenic coating layer as an intermediary substance between the stepped surface and blood. This coating layer specifically comprises a copolymer with carboxybetaine repeating units (1-7 mol%) and methoxyethyl acrylate repeating units (93-99 mol%), which acts as a mediator to prevent direct interaction between blood components and the stepped surface, thereby eliminating thrombus formation while preserving the necessary device structure
Solution Approach 2:
The patent changes the chemical composition parameters of the coating material by using a specific copolymer composition with controlled ratios of carboxybetaine (1-7 mol%) and methoxyethyl acrylate (93-99 mol%) units. This parameter optimization provides both hydrophilicity for blood compatibility and controlled water solubility (0.1-10 wt% at 37°C) to prevent material elution while maintaining antithrombogenicity
2Reliability
If existing antithrombogenic materials are used, then some level of blood compatibility is achieved, but they are insufficient under severe conditions prone to thrombus formation
Solution Approach 1:
The patent employs a composite copolymer material combining two different repeating units: carboxybetaine units (providing antithrombogenic properties) and methoxyethyl acrylate units (providing hydrophilicity and controlling water solubility). This composite structure creates a synergistic effect that delivers superior antithrombogenicity under severe conditions compared to single-component materials, while maintaining structural integrity through controlled solubility
Solution Approach 2:
The patent applies local quality by creating a surface coating layer with specific composition (1-7 mol% carboxybetaine units) that differs from the bulk material properties. The coating layer is designed to provide enhanced antithrombogenicity at the blood-contacting surface while the overall material maintains controlled water solubility to prevent elution, achieving localized optimization for severe conditions
3Reliability
If the copolymer has high water solubility to improve antithrombogenicity, then blood compatibility increases, but material elution occurs
Solution Approach 1:
The patent precisely controls the water solubility parameter of the copolymer by adjusting the ratio of carboxybetaine (1-7 mol%) to methoxyethyl acrylate (93-99 mol%) units. This parameter optimization achieves a balanced state where the material has sufficient hydrophilicity for antithrombogenicity while maintaining limited water solubility (0.1-10 wt% at 37°C) to prevent material elution, resolving the contradiction between blood compatibility and material stability
Data Source
AI summary
A medical device is provided including a base member and a coating layer containing an antithrombogenic material and covering a surface of the base member. The antithrombogenic material contains a copolymer having a repeating unit (A) represented by the following formula (1):wherein R11 is a hydrogen atom or a methyl group, Z is an oxygen atom or —NH—, R12 is a C1-6 alkylene group, R13 and R14 are each independently a C1-4 alkyl group, and R15 is a C1-2 alkylene group, and a repeating unit (B) represented by the following formula (2):wherein R21 is a hydrogen atom or a methyl group, R22 is a C1-6 alkylene group, and R23 is a C1-4 alkyl group. The repeating unit (A) is contained in a proportion of 1 to 7 mol % based on all the structural units of the copolymer.