Sub-threshold Current Inhibits Platelet Adhesion on Implants

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Solution Overview

Problem

Implanted medical devices, such as artificial heart valves, are prone to thrombogenesis due to altered blood flow interactions, leading to blood component adhesion and increased risk of thrombosis and bleeding complications, necessitating lifelong anti-coagulant medication.

Innovation Solution

Applying a sub-threshold electropositive current with a density of between 0.001 and 1 mA/cm² to the surface of implanted medical devices to inhibit blood platelet adhesion and thrombogenesis, using an electrical energy source coupled to the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If anti-coagulant medication is used to prevent thrombosis on implanted medical devices, then the risk of thrombosis is reduced, but the risk of bleeding complications increases

Engineering Contradiction:

Improvethrombosis preventionVSAvoidbleeding complications

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the chemical mechanism of anti-coagulant drugs with an electrical field mechanism. An electrical energy source delivers electropositive current to the implanted medical device surface, creating an electrical field that repels negatively charged blood platelets, preventing their adhesion without affecting the coagulation cascade systemically.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an electrical field as an intermediary between the implanted device and blood components. This electrical field acts as a mediator that selectively interacts with negatively charged platelets through electrostatic repulsion, preventing thrombogenesis without requiring direct chemical interaction with the blood coagulation system.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the electropositive current density is increased to enhance thrombogenesis inhibition, then platelet adhesion is reduced, but tissue excitation may occur

Engineering Contradiction:

Improvethrombogenesis inhibitionVSAvoidtissue excitation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent precisely controls the electropositive current density parameter within a specific range (0.001 to 1 mA/cm²). This parameter optimization ensures sufficient electrical field strength to repel platelets while remaining below the threshold that would excite or damage surrounding biological tissues.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies a sub-threshold current density that is sufficient to achieve platelet repulsion but intentionally kept below levels that would cause tissue excitation. This partial action approach provides effective thrombogenesis inhibition while maintaining safety margins for tissue integrity.

Inventive Principle:

Principle #16Partial or excessive action

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

Substantially inhibits thrombogenesis on implanted medical devices without the need for anti-coagulant medication, reducing the risk of thrombosis and bleeding complications while avoiding tissue excitation.

Implementation Method 1

delivering electropositive current from an electrical energy source to the surface

Methodology Applied

Scientific EffectElectropositive current delivery: Conduction (electrical)

Implementation Method 2

sub-threshold electropositive current...inhibit blood platelet adhesion

Methodology Applied

Scientific EffectElectrostatic repulsion: Electrostatics

Data Source

PatentUS10406355B2System for conditioning surfaces in vivo

Publication Date: 2019.09.10 MEDTRONIC PS MEDICAL INC

AI summary

A system and method for conditioning surfaces of a body in vivo includes providing an electrical energy source, coupling the electric energy source to the surface, and delivering electropositive current from the electrical energy source to the surface so as to generate a sub-threshold current density on the surface. In preferred embodiments, the sub-threshold electropositive current density is between about 0.001 and about 1.0 mA/cm2.