Thin Hydroxyapatite Coating on Titanium Implants
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Solution Overview
Problem
Current implant materials face issues with implant loosening, migration, and infection due to bacterial adherence and biofilm formation, particularly with gram-positive microorganisms like Staphylococcus aureus and Staphylococcus epidermidis, and existing hydroxyapatite (HA) coatings have limitations such as thick coatings, structural alterations, and poor adhesion, which affect antibiotic delivery and long-term clinical application.
Innovation Solution
A method involving anodizing a titanium implant substrate, followed by blasting and coating with a thin or ultra-thin hydroxyapatite (HA) layer using a biomimetic approach, allowing for local antibiotic delivery and enhanced fixation without extensive damage during removal, utilizing a TiO2 coated surface and potentially incorporating therapeutic agents like antibiotics or bisphosphonates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If plasma spraying technique is used for HA coating deposition, then HA coating can be produced, but coating thickness becomes too great (50 μm to 200 μm) and adhesion between coating and metallic substrate deteriorates
Solution Approach 1:
The patent changes the deposition parameters by using electrolytic deposition instead of plasma spraying, controlling the process to produce thin coatings (1-20 μm) rather than thick coatings (50-200 μm). This parameter change resolves the contradiction by achieving appropriate coating thickness while maintaining good adhesion through the electrolytic process mechanism.
Solution Approach 2:
The patent replaces the mechanical plasma spraying system with an electrolytic deposition system. This substitution allows for better control of coating thickness and adhesion by using electrochemical reactions rather than high-velocity particle impact, thereby resolving the adhesion problem associated with thick plasma-sprayed coatings.
2Quantity of substance
If plasma spraying technique is used for HA coating deposition, then HA coating can be produced, but structural alterations in HA occur due to high temperatures
Solution Approach 1:
The patent replaces the thermal plasma spraying process with a non-thermal electrolytic deposition process. This substitution eliminates the high-temperature exposure that causes HA structural alterations, allowing the coating to be deposited while preserving the crystalline structure and chemical composition of the hydroxyapatite.
Solution Approach 2:
The patent changes the processing temperature parameter from high temperature (plasma spraying) to low or ambient temperature (electrolytic deposition). This parameter change prevents thermal degradation of the HA structure while still achieving effective coating deposition on the implant surface.
3Stability of the object's composition
If dense structure HA coating is used, then coating integrity is maintained, but antibiotic incorporation ability is limited
Solution Approach 1:
The patent employs a porous HA coating structure produced through electrolytic deposition. The porous structure provides high surface area and interconnected channels that enable extensive antibiotic incorporation and controlled release, while still maintaining sufficient structural integrity for implant fixation. This resolves the contradiction by showing that porosity enhances rather than compromises coating functionality.
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 method provides fast stabilization and safe removal of implants with improved osseointegration, reduced tissue damage, and extended drug release due to deeper pore penetration, while avoiding the need for NaOH pre-treatment and high process temperatures, resulting in a more effective and efficient implant with enhanced biocompatibility and infection control.
Implementation Method 1
anodizing the titanium implant substrate by an electrolytic process in an alkaline liquid
Implementation Method 2
anodizing the titanium implant substrate by an electrolytic process in an alkaline liquid
Implementation Method 3
blasting the anodized titanium implant substrate
Data Source
AI summary
A method of manufacturing an implant for use in a surgical procedure, a corresponding implant and the use thereof during the incorporation of a substance is presented. Specifically anodized and blasted titanium implant substrates are provided with a hydroxyapatite (HA) coating for incorporating for example a therapeutic agent. In particular, an anodizing procedure by an electrolytic process in an alkaline liquid is carried out. Moreover, blasting of the anodized titanium implant substrate is carried out by the presented method. The HA coating can be in the range of 1 to 5 μm, particularly in the range of 1 to 3 μm. A local delivery of the active pharmaceutical ingredient is achieved by the implant of the present invention. Moreover, the implant allows for the removal of the implant without damaging surrounding tissue or a bone. Moreover, the HA coating is provided to the substrate such that enhanced fixation as measured by pull-out force is achieved whilst having a relatively low removal torque. The HA coating and drug incorporation may be carried out sequentially but also co-precipitation approach can be used.