Antithrombogenic Coating via Segmented Ionic and Covalent Bonding
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Solution Overview
Problem
Existing antithrombogenic materials face challenges such as limited degree of freedom in heparin or heparin derivative bonding, elution issues due to phase separation, and inadequate control over anticoagulant activity, leading to reduced effectiveness and potential hemolytic toxicity.
Innovation Solution
An antithrombogenic material comprising a polymer with cationic monomers like alkyleneimines and an anionic compound with sulfur atoms, such as heparin, covalently bound to a base material, with specific abundance ratios of nitrogen and sulfur atoms to ensure stable ionic bonding and controlled elution, maintaining high antithrombogenicity and cellular adhesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heparin or heparin derivative is covalently bound to the surface of the base material, then the bonding strength is improved, but the degree of freedom of heparin decreases and anticoagulant activity is reduced
Solution Approach 1:
The patent divides the bonding mechanism into two separate functions: covalent bonding of the cationic compound to the base material provides structural anchoring, while ionic bonding of heparin to the cationic compound maintains heparin's flexibility and anticoagulant activity. This segmentation resolves the contradiction by assigning different bonding types to different functional requirements.
Solution Approach 2:
The cationic compound acts as an intermediary between the base material and heparin. It provides a stable platform through covalent bonding while presenting positive charges for ionic interaction with heparin, thereby mediating between the need for strong attachment and preservation of heparin's functional freedom.
2Adaptability or versatility
If heparin or heparin derivative is bound by ionic bonding to a positively charged cationic compound, then the degree of freedom and anticoagulant activity are improved, but elution occurs with time
Solution Approach 1:
The cationic compound is pre-bound to the base material surface through covalent bonding before heparin is introduced. This preliminary anchoring creates a stable platform that prevents heparin from detaching, as any elution would require breaking both the covalent bonds of the cationic compound and the ionic bonds of heparin simultaneously.
Solution Approach 2:
The patent merges two bonding mechanisms: covalent bonding for the cationic compound to the base material and ionic bonding for heparin to the cationic compound. This combination creates a dual-bonding system where the strong covalent anchor prevents overall detachment while the ionic bond maintains heparin's functional properties.
3Adaptability or versatility
If various combinations with positively charged cationic compounds are studied to control elution rate, then the control over anticoagulant activity is improved, but device complexity increases
Solution Approach 1:
The patent controls anticoagulant activity by adjusting parameters of the cationic compound (charge density, molecular weight, structure) rather than using multiple different cationic compounds. This allows tuning of heparin binding strength and elution rate through parameter optimization of a single class of compounds, reducing complexity.
4Reliability
If the amount of heparin or heparin derivative bound is increased to maintain antithrombogenicity, then the anticoagulant activity is improved, but hemolytic toxicity increases
Solution Approach 1:
The cationic compound serves as a mediator that binds heparin in a controlled manner, allowing sufficient heparin to be present for anticoagulant activity while the structured binding prevents excessive free heparin that would cause hemolysis. The intermediary controls the availability and distribution of heparin on the surface.
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 material effectively prevents blood coagulation on medical devices for extended periods with reduced hemolytic toxicity, maintaining the structural integrity of the surface and ensuring effective anticoagulant activity.
Implementation Method 1
heparin or a heparin derivative is bound by ionic bonding to a positively charged cationic compound introduced to the surface of the base material
Implementation Method 2
an anionic compound containing a sulfur atom and having anticoagulant activity; wherein the polymer is covalently bound to the base material
Data Source
AI summary
The present invention aims to provide an antithrombogenic material which is highly safe with its low hemolytic toxicity, and capable of maintaining high antithrombogenicity for a long period. The present invention provides an antithrombogenic material comprising: a coating material containing a polymer containing, as a constituent monomer, a compound selected from the group consisting of alkyleneimines, vinylamines, allylamines, lysine, protamine, and diallyldimethylammonium chloride, and an anionic compound containing a sulfur atom and having anticoagulant activity; and a base material whose surface is coated with the coating material; wherein the polymer is covalently bound to the base material, and the abundance ratio of nitrogen atoms to the abundance of total atoms as measured by X-ray photoelectron spectroscopy on the surface is 6.0 to 12.0 atomic percent.