Endovascular Stent Coating Using CD31 Peptides to Reduce Thrombosis
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Solution Overview
Problem
Medical devices often trigger a foreign body response, leading to chronic inflammation, thrombosis, and vascular obstruction due to non-biocompatible materials, which complicates the use of valvular and vascular devices for cardiovascular treatments.
Innovation Solution
Development of biomimetic peptides that mimic the trans-homophilic CD31-CD31 interaction to promote endothelialization and prevent excessive platelet activation, using a three-step dip-coating process with polydopamine, linker, and peptide grafting to create a biocompatible surface on medical devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-biocompatible materials are used for medical devices, then device structural integrity and mechanical strength are maintained, but foreign body response is triggered leading to chronic inflammation and thrombosis
Solution Approach 1:
The invention uses a composite coating structure consisting of polydopamine base layer and CD31 peptide functional layer. This composite approach combines the mechanical stability of polydopamine with the biocompatibility and endothelialization-promoting properties of CD31 peptides, resolving the contradiction between structural integrity and foreign body response prevention.
Solution Approach 2:
The coating applies different functional layers with specific properties: polydopamine provides general adhesion and surface stability, while the CD31 peptide layer specifically targets endothelial cell adhesion and anti-thrombotic properties. This local differentiation of material properties allows simultaneous achievement of mechanical strength and biocompatibility.
2Ease of manufacture
If conventional coating methods are used, then manufacturing process is simple, but endothelialization is delayed and platelet activation remains excessive
Solution Approach 1:
The polydopamine layer is applied first as a preliminary step to create a stable surface that enhances subsequent peptide adhesion. This preliminary action simplifies the overall process by providing a universal adhesion platform, while the followed CD31 peptide grafting ensures high endothelialization efficiency.
Solution Approach 2:
Polydopamine acts as an intermediary layer between the device surface and the CD31 peptides. It facilitates the attachment of peptides to the device surface and enhances their stability, thereby improving endothelialization efficiency while maintaining manufacturing simplicity through a straightforward dip-coating process.
3Object-affected harmful factors
If CD31-mimetic peptides are immobilized on device surface, then platelet adhesion is reduced and endothelialization is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The polydopamine coating possesses self-assembling properties that enable uniform coverage of the device surface through dip-coating. This self-service characteristic reduces the need for complex manufacturing controls, achieving consistent peptide immobilization and effective platelet adhesion reduction with simple processing.
Solution Approach 2:
The dip-coating process allows control of coating thickness and uniformity by adjusting simple parameters such as immersion speed, withdrawal speed, and coating concentration. These parameter changes enable precise control of peptide distribution without requiring complex manufacturing equipment or procedures.
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 biomimetic peptides facilitate rapid endothelial layer formation, reducing platelet adhesion and inflammation, potentially eliminating the need for prolonged anti-platelet therapy and minimizing complications like thrombosis and restenosis.
Implementation Method 1
a first step for a polydopamine coating
Implementation Method 2
polydopamine coating
Implementation Method 3
a second step for grafting a suitable linker, and a third step for the coating with the invention peptide
Data Source
AI summary
Inventors have synthesized peptides allowing an engagement of intact CD31 molecules on all the healthy endothelial cells and resting blood platelets and leukocytes that can enter in contact with an implanted device. Those cells can therefore receive the “leave-me-alone” signal delivered by the trans-homophilic engagement of CD31, which is essential to maintain the homeostasis in the circulation and vascularized tissues. Thrombotic or life-threatening occurrence of hemorrhagic or thromboembolic complications have impaired the use of endovascular devices. The devices bearing the mimicking peptides of the present invention are rapidly integrated, because they are perceived by blood platelets and leukocytes as a healthy endothelium, a “self’ component. Furthermore, their ability to be rapidly endothelialized with a physiologic endothelial cell phenotype also limits platelet and leukocyte activation at the site of device implantation in the long-term. Accordingly, the present invention relates to peptides mimicking the trans-homophilic CD31-CD31 domain 1 and 2 intercellular interaction.