ALD Titanium Nitride Coating for Joint Implants

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Solution Overview

Problem

Joint replacement implants experience wear and tear, leading to loosening and complications such as bone loss, infection, and the need for revision surgery due to friction and bacterial adherence on metal and plastic surfaces, which existing technologies have not adequately addressed.

Innovation Solution

A method using atomic layer deposition (ALD) to apply a low-friction coating on contact surfaces and an adhesion-promoting coating on non-contact surfaces of joint endoprostheses, specifically using titanium nitride and titanium oxynitride compounds to reduce friction and enhance tissue integration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal-on-metal or metal-on-plastic surfaces are used in joint implants, then the implant can provide structural support and movement, but friction and wear between surfaces cause implant loosening and bone loss

Engineering Contradiction:
Improvestructural supportVSAvoidimplant stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies different coating compositions to different regions of the implant surface. The hydrophobic region coating reduces friction and wear, while the hydrophilic region coating promotes osteoblast adhesion and bone integration. This local differentiation resolves the contradiction by allowing the bearing surface to minimize wear while the bone-contact surface maximizes structural integration.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite coating structures combining hydrophobic and hydrophilic regions on the implant surface. This composite approach allows simultaneous achievement of low-friction wear resistance in the bearing area and high adhesion strength in the bone integration area, resolving the contradiction between structural support and implant stability.

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional coating methods (PVD or CVD) are used to reduce friction, then wear resistance improves, but the coating cannot simultaneously promote bone adhesion and prevent bacterial biofilm formation

Engineering Contradiction:
Improvewear resistanceVSAvoidmulti-functionality
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent divides the implant surface into distinct functional zones: hydrophobic regions for low-friction wear resistance and hydrophilic regions for bone adhesion and bacterial resistance. This local quality differentiation allows the coating to perform multiple functions simultaneously, resolving the contradiction between wear resistance and multi-functionality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The coating is segmented into functionally distinct hydrophobic and hydrophilic regions. This segmentation enables each region to specialize in its primary function (friction reduction or adhesion promotion) while collectively providing comprehensive protection against wear, infection, and loosening.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If metal and plastic surfaces are used in joint implants, then the implant can function mechanically, but bacteria can adhere to surfaces forming antibiotic-resistant biofilms

Engineering Contradiction:
Improvemechanical functionVSAvoidbacterial adherence
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent creates hydrophilic regions on the implant surface that specifically resist bacterial adhesion while maintaining mechanical functionality. The hydrophilic surface properties prevent bacterial colonization without compromising the structural and mechanical performance of the implant.

Inventive Principle:
Principle #3Local quality

4Ease of manufacture

If a single coating composition is applied to the entire implant surface, then the manufacturing process is simple, but the coating cannot simultaneously reduce friction, promote bone adhesion, and prevent infection

Engineering Contradiction:
Improvecoating process simplicityVSAvoidcomprehensive protection
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies different coating compositions to different regions of the implant surface based on their specific functional requirements. This localized approach provides comprehensive protection against wear, infection, and loosening while maintaining a relatively simple manufacturing process through selective area coating.

Inventive Principle:
Principle #3Local quality

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 significantly reduces wear and tear, prevents bacterial adherence, and promotes bone integration, thereby minimizing the risk of complications and the need for revision surgery, while being cost-effective and versatile in application.

Implementation Method 1

a method for depositing a coating film or films with atomic layer deposition (ALD) on the surfaces of at least two separate elements (11A, 11B)

Methodology Applied
Scientific EffectAtomic layer deposition: Chemical Vapour Deposition

Implementation Method 2

on the non-contact surfaces (14A, 14B) of each said element, ALD-depositing an adhesion-improving coating film configured to promote adhesion of the endoprosthesis to a surrounding tissue

Methodology Applied
Scientific EffectAtomic layer deposition: Chemical Vapour Deposition

Data Source

PatentEP3714911B1Coating for joint implants
Publication Date: 2023.02.15 PICOSUN OY
  • EP3714911B1 patent drawingFigure 1
  • EP3714911B1 patent drawingFigure 2

AI summary

A method for depositing a coating layer on at least a part of a joint endoprosthesis with atomic layer deposition (ALD), wherein said coating layer comprises a metal compound, preferably, a titanium nitride based compound.