Anodized Titanium Silver Implant Surface

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Solution Overview

Problem

Current methods for antimicrobial surface treatment of titanium and titanium alloys with silver lack controlled release of silver ions, which is essential for maintaining antimicrobial efficacy without cytotoxicity.

Innovation Solution

The method involves anodizing titanium surfaces in the presence of a silver-yielding substance, such as silver nitrate, with a reducing agent like sodium borohydride, allowing for controlled incorporation of silver ions into the surface layer, either through Type II or Type III anodizing, or physical gas phase deposition, to achieve a sustained release of silver ions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If silver is deposited on titanium surface using conventional methods (PVD, ion implantation), then antimicrobial provision is achieved, but controlled release of silver ions over time is not possible

Engineering Contradiction:

Improveantimicrobial effectivenessVSAvoidduration of silver ion release

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent utilizes porous anodized titanium layers as a substrate for silver deposition. The porous structure provides high surface area and controlled diffusion pathways, enabling sustained release of silver ions over extended periods while maintaining antimicrobial effectiveness

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent creates a composite structure by depositing silver onto anodized titanium surfaces. This composite material combines the beneficial properties of titanium (biocompatibility, strength) with silver (antimicrobial activity) and the controlled release characteristics of the anodized porous layer

Inventive Principle:

Principle #40Composite materials

2Reliability

If high concentration of silver ions is released to ensure antimicrobial efficacy, then antimicrobial effectiveness is improved, but cytotoxicity to surrounding tissue increases

Engineering Contradiction:

Improveantimicrobial effectivenessVSAvoidcytotoxicity to surrounding tissue

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements periodic or sustained low-level release of silver ions through the anodized layer structure, rather than rapid high-concentration release. This temporal control maintains antimicrobial pressure on pathogens while allowing surrounding tissue to recover, reducing cytotoxicity

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent concentrates silver ions at the implant-tissue interface where they are most needed for antimicrobial protection, while the anodized layer controls diffusion to prevent excessive silver concentration in surrounding healthy tissue, thereby localizing the therapeutic effect and minimizing systemic toxicity

Inventive Principle:

Principle #3Local quality

3Reliability

If multiple separate processes are used for surface treatment and silver deposition, then each function can be optimized, but process complexity increases

Engineering Contradiction:

Improvesurface hardness and wear resistanceVSAvoidnumber of processing steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines surface treatment (anodizing) and silver deposition into a single integrated process. The anodization step creates the porous titanium oxide layer that simultaneously serves as a surface treatment for hardness enhancement and as a substrate for silver deposition, eliminating the need for separate processing steps

Inventive Principle:

Principle #5Merging (Combining)

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

This approach enables a controlled and prolonged release of silver ions, maintaining antimicrobial effectiveness for at least 10 days while minimizing cytotoxicity, with silver concentrations in living tissue ranging from 0.5 ppb to 50 ppb after 24 hours, ensuring both efficacy and safety.

Implementation Method 1

anodizing of the implant surface in the presence of an electrolyte

Methodology Applied

Scientific EffectAnodizing: Anodising

Implementation Method 2

anodizing of Type II... anodizing of Type III

Methodology Applied

Scientific EffectElectrochemical oxidation: Oxidation

Implementation Method 3

the silver is at least partially reduced from silver ions by a reducing agent

Methodology Applied

Scientific EffectReduction: Reduction

Implementation Method 4

the electrolyte comprises a silver-yielding substance... the electrolyte comprises the reducing agent

Methodology Applied

Scientific EffectElectrolyte conduction: Electrolysis

Implementation Method 5

physical gas phase deposition

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS9011668B2Antimicrobial provision of titanium and titanium alloys with silver

Publication Date: 2015.04.21 STRYKER EUROPEAN OPERATIONS HOLDINGS LLC

AI summary

A method for the antimicrobial provision of implant surfaces with silver, in which the method comprises an anodizing of the implant surface with an electrolyte, in which the electrolyte has a silver-yielding substance. Alternatively, the method comprises a silver implantation or a silver PVD deposition.