Evanescent Calcium Phosphate Coating for Controlled Antibacterial Release
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Solution Overview
Problem
Current bioimplants face challenges in controlling the sustained release of antibiotics from hydroxyapatite coatings, leading to unpredictable antibacterial activity and difficulty in preventing postoperative infectious diseases, especially since inorganic antibacterial agents are insoluble and have low elution rates from crystalline hydroxyapatite films.
Innovation Solution
A bioimplant with an evanescent coating film made of calcium phosphate-based materials having crystallinity of 90% or less, which allows for controlled release of antibacterial agents or antibiotics by adjusting the film's evanescence rate and period, enabling the use of insoluble inorganic agents and preventing infectious diseases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a crystalline hydroxyapatite coating film is used for antibiotic impregnation, then the coating provides good bone adhesion and structure, but the uniform pore size and porosity make it difficult to achieve sustained release of medicine at a desired rate
Solution Approach 1:
The patent changes the crystallinity parameter of the hydroxyapatite coating film from high (crystalline) to low (amorphous or partially crystalline) to achieve different release rates. The amorphous coating provides sustained release while the crystalline coating provides rapid release, allowing control over medicine delivery timing and rate.
2Ease of operation
If a water-soluble natural organic antibacterial agent is used, then the agent can be eluted from the hydroxyapatite structure, but the antibacterial activity is lower and resistant bacteria are easily generated
Solution Approach 1:
The patent changes the solubility parameter of the antibacterial agent from water-soluble (organic) to insoluble (inorganic) form. Inorganic antibacterial agents like silver particles or zinc oxide are used instead, providing higher antibacterial activity and preventing resistance while being released through coating erosion rather than dissolution.
3Reliability
If an inorganic antibacterial agent is used to prevent infectious diseases, then high antibacterial activity is achieved, but the agent is insoluble and difficult to utilize elution from crystalline hydroxyapatite film
Solution Approach 1:
The patent changes the coating structure from crystalline to amorphous or partially crystalline to enable elution of insoluble inorganic antibacterial agents. The amorphous coating erodes more readily in physiological environment, releasing the insoluble antibacterial agents gradually, thus utilizing the erosion phenomenon for sustained release.
4Strength
If the coating film has high crystallinity for structural stability, then the film maintains good mechanical properties, but the evanescence rate cannot be controlled for sustained medicine release
Solution Approach 1:
The patent changes the crystallinity parameter of the coating film to create a gradient structure or use amorphous phases that erode at controlled rates. This allows the coating to maintain sufficient structural stability while enabling predictable erosion and sustained release of antibacterial agents over extended periods.
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 controlled release of antibacterial agents creates an optimal antibacterial environment for a predetermined period, effectively preventing postoperative infections and reducing the risk of artificial joint withdrawal, immobilization, and amputation.
Implementation Method 1
an evanescent coating film made of a calcium phosphate-based material having crystallinity of 90% or less... the evanescent coating film containing an antibacterial agent or an antibiotic... controlled release of antibacterial agents
Implementation Method 2
calcium phosphate-based material having crystallinity of 90% or less... allows for controlled release of antibacterial agents or antibiotics by adjusting the film's evanescence rate and period
Data Source
AI summary
To provide a bioimplant capable of controlling a rate of an antibacterial agent and an antibiotic to be eluted from the coating film. An evanescent coating film made of a calcium phosphate-based material having crystallinity of 10% to 90% is formed at a predetermined area of the bioimplant and an antibacterial agent or an antibiotic is contained in the coating film to suppress adhesion of bacteria.