Composite Thin Film Lead for Deep Brain Stimulation

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Solution Overview

Problem

Existing thin film leads for deep brain stimulation have high electrical resistance due to the limited conductivity of platinum, which poses challenges in maintaining biocompatibility and magnetic resonance compatibility, especially in long, narrow traces, where increasing platinum thickness is not feasible without introducing stress and topology issues.

Innovation Solution

A thin film lead comprising a high conductive metal, such as gold, partially encapsulated by a low conductive biocompatible metal like platinum, with additional encapsulation by a ceramic material and a flexible polymer, and processed using techniques like sputter deposition and electroplating to enhance conductivity while maintaining biocompatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If platinum is used as the conductive metal in thin film leads, then biocompatibility is improved, but electrical conductivity deteriorates

Engineering Contradiction:

ImprovebiocompatibilityVSAvoidelectrical conductivity

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent employs a composite metal structure where a high-conductivity metal core (such as copper, aluminum, or silver) is completely encapsulated by a biocompatible metal shell (such as platinum, titanium, or titanium nitride). This composite structure combines the high electrical conductivity of the inner metal with the biocompatibility of the outer metal shell, resolving the contradiction between conductivity and biocompatibility in thin film leads for deep brain stimulation applications.

Inventive Principle:

Principle #40Composite materials

2Loss of energy

If platinum thickness is increased to reduce resistance, then electrical conductivity is improved, but mechanical stress and topology issues worsen

Engineering Contradiction:

Improveelectrical resistanceVSAvoidmechanical stress

Core Design Contradiction:

Loss of energyVSStability of the object's composition

Solution Approach 1:

The patent changes the material parameter from using thick platinum to using a thin shell of biocompatible metal (platinum, titanium, or titanium nitride) encapsulating a high-conductivity metal core. This parameter change allows achieving low resistance without increasing platinum thickness, thereby avoiding the mechanical stress and topology issues that arise from thick platinum layers in narrow traces.

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If high conductive metals like copper or aluminum are used, then electrical conductivity is improved, but biocompatibility deteriorates

Engineering Contradiction:

Improveelectrical conductivityVSAvoidbiocompatibility

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent uses composite materials where high-conductivity metals (copper, aluminum, or silver) serve as the inner core for optimal electrical conductivity, while a biocompatible metal shell (platinum, titanium, or titanium nitride) provides the biocompatible interface with brain tissue. This composite structure allows the high-conductivity metal to function electrically without direct biological exposure, resolving the contradiction between conductivity and biocompatibility.

Inventive Principle:

Principle #40Composite materials

4Adaptability or versatility

If thin film traces are made longer for deeper brain penetration, then application versatility is improved, but electrical resistance worsens

Engineering Contradiction:

Improvedeep brain penetration capabilityVSAvoidelectrical resistance

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent employs composite metal traces with high-conductivity cores (copper, aluminum, or silver) encapsulated in biocompatible shells, enabling longer trace lengths for deeper brain penetration while maintaining low electrical resistance. The high-conductivity core allows efficient current transmission over extended lengths, overcoming the resistance issue that would otherwise limit deep brain stimulation lead design.

Inventive Principle:

Principle #40Composite materials

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 solution reduces the resistivity of the thin film leads, enabling longer, more flexible designs with improved electrical conductivity and biocompatibility, ensuring effective deep brain stimulation while maintaining magnetic resonance compatibility.

Implementation Method 1

at least one section comprising a high conductive metal and a low conductive metal, whereby the low conductive metal is a biocompatible metal and has a lower electrical conductivity than the high conductive metal

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 2

sputter depositing a platinum layer

Methodology Applied

Scientific EffectSputter deposition: Sputtering

Implementation Method 3

platinum electroplating of traces

Methodology Applied

Scientific EffectElectroplating: Electroplating

Data Source

PatentUS9956396B2Thin film for a lead for brain applications

Publication Date: 2018.05.01 MEDTRONIC BAKKEN RES CENT

AI summary

A thin film for a lead for brain applications includes at least one section comprising a high conductive metal and a low conductive metal, whereby the low conductive metal is a biocompatible metal and has a lower electrical conductivity than the high conductive metal and whereby the high conductive metal is at least partially encapsulated by the low conductive metal. Furthermore, the present invention relates to a method of manufacturing a thin film for a lead for brain applications and a deep brain stimulation system.