Negative Poisson's Ratio Coatings for Bone Implants

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Solution Overview

Problem

Medical implants face challenges in maintaining homeostasis and promoting healthy bone growth due to issues with stress and strain distribution at the bone-implant interface, as existing materials tend to expand or compress in ways that can overstress tissues over time.

Innovation Solution

Incorporating negative Poisson's ratio (NPR) materials into medical implants, such as bone plates and prostheses, which compress in response to compression and expand in response to tension, reducing stress on bones and joints, and promoting bone ingrowth through specific coatings and structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If positive Poisson's ratio materials are used in medical implants, then the implant structure is simple and easy to manufacture, but the implant causes excessive stress and strain on bone tissues over time

Engineering Contradiction:

Improveease of manufactureVSAvoidstress on bone tissues

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the Poisson's ratio parameter from positive (conventional) to negative (auxetic), fundamentally altering the material's mechanical response. This parameter change enables the implant to compress under compression and expand under tension, reducing harmful stress on bone tissues while maintaining manufacturing feasibility through controlled material synthesis processes

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional materials are used for medical implants, then the manufacturing process is straightforward, but the implant fails to maintain homeostasis and promote healthy bone growth

Engineering Contradiction:

Improveease of manufactureVSAvoidhomeostasis maintenance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

By changing the Poisson's ratio to negative, the material actively responds to mechanical stimuli in a way that maintains homeostasis. The auxetic properties enable the implant to adapt to bone remodeling processes, promoting healthy bone growth and maintaining stable mechanical conditions at the bone-implant interface

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures combining auxetic materials with conventional implant components. This composite approach integrates the homeostasis-maintaining properties of negative Poisson's ratio materials with the structural requirements of traditional implants, achieving both reliability and functional performance

Inventive Principle:

Principle #40Composite materials

3Object-affected harmful factors

If positive Poisson's ratio materials are used, then the implant expands under compression which can cause tissue damage, but using negative Poisson's ratio materials requires specialized material synthesis

Engineering Contradiction:

Improvetissue damageVSAvoidease of manufacture

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by synthesizing materials with negative Poisson's ratio through controlled foam structures and material composition. This specialized material synthesis enables the implant to compress under compression and expand under tension, preventing tissue damage while the manufacturing complexity is managed through established auxetic material fabrication techniques

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

NPR materials help maintain optimal stress and strain conditions, reducing the risk of tissue damage, promoting healthy bone growth, and improving the longevity and stability of implants by distributing loads effectively and regulating bone mass.

Implementation Method 1

Incorporating negative Poisson's ratio (NPR) materials into medical implants, such as bone plates and prostheses, which compress in response to compression and expand in response to tension

Methodology Applied

Scientific EffectNegative Poisson's ratio: Auxetic Materials

Data Source

PatentUS20250001048A1Medical implants including negative poisson's ratio materials

Publication Date: 2025.01.02 PARK JOON BU

AI summary

A medical implant includes a first implant body and a pre-coating covering at least a portion of an outer surface of the first implant body. The pre-coating has a negative Poisson's ratio. A method of making a medical implant includes applying a precursor material on a surface of a first implant body, the first implant body having a positive Poisson's ratio. A stimulus is applied to the precursor material, the stimulus causing the precursor material to form a coating having a negative Poisson's ratio