Magnesium Implant Hydrogen Binding Coating
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Solution Overview
Problem
Biodegradable magnesium implants, such as stents, face issues with uncontrollable degradation and mechanical integrity loss due to hydrogen release, leading to premature failure and variability in degradation times, especially under mechanical stress and deformation.
Innovation Solution
A hydrogen-binding palladium coating is applied to the implant surface to absorb and store hydrogen, combined with a parylene or magnesium stearate layer for enhanced protection, and a plasma-chemical treatment to form a porous intermediate layer, allowing controlled degradation and maintaining mechanical stability during deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a protective coating is applied to slow down degradation, then degradation rate is reduced, but mechanical integrity is compromised during deformation
Solution Approach 1:
The protective layer is segmented into multiple functional layers: a palladium-containing layer for hydrogen binding, an intermediate layer for adhesion and porosity control, and an outer barrier layer for mechanical protection. This segmentation allows each layer to perform its specific function without compromising overall mechanical integrity during deformation.
Solution Approach 2:
The protective coating is formed as a composite structure combining palladium particles (for hydrogen binding), polymer matrices (for mechanical flexibility), and ceramic or metallic barrier materials (for corrosion protection). This composite approach enables simultaneous achievement of controlled degradation and maintained mechanical strength during deformation.
2Reliability
If palladium coating is applied to bind hydrogen, then degradation is controlled, but manufacturing complexity increases
Solution Approach 1:
The palladium-containing protective layer is applied to the implant surface before the implant is implanted into the patient. This preliminary coating action ensures that hydrogen binding capacity is already in place to control degradation during the implant's service life, eliminating the need for complex in-situ treatments or post-implant modifications.
Solution Approach 2:
An intermediate layer is introduced between the palladium-containing layer and the implant substrate. This intermediate layer serves as a mediator that facilitates adhesion of the palladium particles to the implant surface while maintaining the desired porosity and mechanical properties, thereby simplifying the manufacturing process compared to direct palladium deposition.
3Stability of the object's composition
If porous intermediate layer is formed by plasma-chemical treatment, then adhesion is improved, but surface finish deteriorates
Solution Approach 1:
The plasma-chemical treatment is applied selectively to create a porous intermediate layer only in regions where adhesion is most critical, such as at the interface between the protective coating and the implant substrate. The surface finish is maintained in other regions where smoothness is important, achieving local optimization of both adhesion and surface quality.
Solution Approach 2:
The intermediate layer is designed with controlled porosity through plasma-chemical treatment, creating a porous structure that enhances adhesion by providing mechanical interlocking and chemical bonding sites. The pore size and distribution are controlled to maintain surface finish requirements while achieving adequate adhesion strength.
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 palladium coating significantly slows down the degradation of magnesium implants by binding hydrogen, while the additional layers ensure controlled release and increased mechanical integrity, aligning with the desired degradation timeline and maintaining structural stability during dilation or deformation.
Implementation Method 1
A hydrogen-binding palladium coating is applied to the implant surface to absorb and store hydrogen
Implementation Method 2
a plasma-chemical treatment to form a porous intermediate layer
Data Source
AI summary
The implant has a body comprising a largely biodegradable metallic material e.g. magnesium or a magnesium alloy. The implant has a layer on a portion of a surface of the body of the implant, where the layer contains a hydrogen-binding material i.e. palladium. The layer has a layer thickness of approximately 2 micrometers to approximately 6 micrometers. The implant has another layer comprising parylene and/or magnesium stearate arranged over the former layer on a portion of the surface of the implant body. The layer is applied by a galvanic treatment in an aqueous solution such that the aqueous solution contains a water-soluble conductive salt, potassium dihydrogen phosphate, a chelating agent, optionally citric acid, ethylenediaminetetraacetic acid, tartaric acid, a metal compound containing palladium, a compound from a group comprising palladium-II acetate trimer and tris dipalladium. The aqueous solution for producing the intermediate layer contains ions selected from a group of phosphate ions, potassium ions and calcium ions. An independent claim is also included for a method for manufacturing a degradation-inhibiting layer structure on a surface of an implant body.