Gasdynamic Atomization for Medical Implant Coating Morphology Control

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Solution Overview

Problem

Existing methods for forming coatings on medical implants and tissue surfaces lack control over particle formation and deposition, leading to uneven distribution, reduced biocompatibility, and inefficient drug delivery due to excessive solvent residuals and poor morphology control.

Innovation Solution

A versatile spraying process and apparatus that atomizes a liquid composition into submicron droplets, allowing for precise control of coating morphology by adjusting the amount of submicron sized droplets and gas stream interactions, ensuring homogeneous coatings with improved adhesion and drug diffusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional coating processes are used, then coating can be applied to medical implants, but the coating morphology is poorly controlled leading to uneven distribution and decreased biocompatibility

Engineering Contradiction:

Improvecoating morphology controlVSAvoidbiocompatibility

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling atomization parameters (gas pressure, liquid flow rate, nozzle geometry) and deposition parameters (substrate temperature, distance from nozzle) to achieve controlled particle formation and uniform coating morphology in the nano-micrometer range, directly resolving the contradiction between manufacturing precision and biocompatibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces conventional mechanical coating methods with a gasdynamic atomization system where high-velocity gas streams break up liquid coatings into fine particles that deposit uniformly on substrates, achieving superior morphology control and biocompatibility through fluid dynamic control rather than mechanical application

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If conventional atomization is used, then coating can be deposited, but particle size control is insufficient leading to non-homogeneous coatings

Engineering Contradiction:

Improveparticle size controlVSAvoidcoating uniformity

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent employs parameter changes by systematically adjusting atomization pressure, liquid composition viscosity, nozzle orifice dimensions, and gas-to-liquid ratio to produce monodisperse particles with precise size control in the nano-micrometer range, ensuring homogeneous coating deposition

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback control by monitoring particle size distribution during atomization and adjusting operating parameters in real-time to maintain consistent particle dimensions and coating uniformity, preventing deviations in coating quality

Inventive Principle:

Principle #23Feedback

3Ease of manufacture

If high solvent content is used in coating composition, then coating can be applied smoothly, but excessive solvent residuals remain decreasing therapeutic substance potency

Engineering Contradiction:

Improvecoating application smoothnessVSAvoidtherapeutic substance potency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent utilizes phase transitions by controlling the evaporation of volatile solvents during the atomization and deposition process, where the rapid transition from liquid to vapor phase eliminates excess solvent before coating formation, preventing solvent residuals while maintaining smooth coating application

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The patent replaces thermal drying processes with gasdynamic atomization that inherently removes solvents through high-velocity gas flow and rapid evaporation during particle formation, achieving solvent elimination without compromising therapeutic substance integrity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Quantity of substance

If conventional coating methods are used, then coating can be formed, but drug load and drug release are insufficiently controlled

Engineering Contradiction:

Improvedrug load controlVSAvoiddrug release control

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by controlling liquid composition concentration, atomization rate, and deposition conditions to precisely regulate the amount of therapeutic substance incorporated into the coating (drug load) and the rate at which it releases, achieving dual control over quantity and release kinetics

Inventive Principle:

Principle #35Parameter changes

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 process achieves reproducible, homogeneous coatings with enhanced biocompatibility and drug delivery efficiency, minimizing solvent residuals and optimizing surface features for improved adhesion and drug release.

Implementation Method 1

atomizing the liquid composition so that droplets having an initial median droplet size of less than four microns are produced

Methodology Applied

Scientific EffectAtomization:

Implementation Method 2

a second conduit for flowing a first gas stream from a second inlet to a second orifice

Methodology Applied

Scientific EffectGas stream interaction:

Implementation Method 3

particles are formed from the non-volatile component of the liquid composition

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 4

depositing the particles on the substrate to form a coating with a desired morphology

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Data Source

PatentUS8287938B1Method to produce a coating and to fine-tune the coating morphology

Publication Date: 2012.10.16 SCHEER INGO

AI summary

This invention relates to a method to produce reproducible and homogeneous coatings and to fine-tune the coating morphology. More particularly, the invention relates to a method and apparatus for controlling the particle formation and deposition process to form a biocompatible coating on a medical implant or a tissue.