PMMA Bone Cement Dye Solubilizer

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Solution Overview

Problem

Polymethylmethacrylate (PMMA) bone cements are difficult to visually differentiate from bone tissue due to their white to pale-yellow color, and existing dye solutions, such as chlorophyll, have poor solubility in methylmethacrylate, requiring additional complex natural products like refined peanut oil, which pose composition variability issues and risk of dye migration.

Innovation Solution

Incorporating 0.001-1.00 mass percent of a dye or dye mixture insoluble in methacrylic acid methyl ester and 0.001-2.00 mass percent of a synthetically produced, protein-free, hydrophobic, low-molecular solubilizer into the monomer liquid, ensuring homogeneous distribution and stability within the PMMA bone cement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If chlorophyll is used to dye PMMA bone cement, then visual differentiation from bone tissue is improved, but solubility and homogeneous distribution deteriorate due to poor solubility in methylmethacrylate

Engineering Contradiction:
Improvevisual differentiationVSAvoidsolubility and homogeneous distribution
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent introduces a solubilizer as an intermediary substance that mediates between the hydrophobic chlorophyll dye and the methylmethacrylate monomer. The solubilizer has both hydrophobic character to dissolve the dye and compatibility with methylmethacrylate to enable homogeneous distribution throughout the cement matrix, thus resolving the solubility contradiction.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite dyeing system combining chlorophyll, solubilizer, and methylmethacrylate in specific proportions. This composite approach allows the incompatible components (hydrophobic dye and monomer) to coexist homogeneously through the synergistic interaction of the solubilizer, achieving both visual differentiation and compositional stability.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If refined peanut oil is added to improve dye solubility, then solubility is improved, but composition variability and complexity worsen due to natural product variations

Engineering Contradiction:
Improvedye solubilityVSAvoidcomposition variability
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent replaces complex natural products (refined peanut oil) with simpler, more stable synthetic or semi-synthetic solubilizers. These alternative solubilizers provide consistent composition without the variability inherent in natural products, while maintaining the necessary solubility-enhancing function.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical parameters of the solubilizer by selecting substances with specific molecular weights, hydrophobicity levels, and functional groups that provide consistent performance. This parameter optimization ensures reproducible dye solubility without the composition variability of natural products.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If dye pigments are added to monomer liquid or powder component, then visual differentiation is improved, but dye migration and release risk worsen

Engineering Contradiction:
Improvevisual differentiationVSAvoiddye migration risk
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent performs preliminary dissolution of the dye in the solubilizer-monomer mixture before polymerization occurs. This preliminary action ensures the dye is uniformly distributed and molecularly dispersed in the liquid phase before the cement sets, preventing subsequent migration that would occur with post-mixing addition.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates local homogeneity at the molecular level by ensuring complete dissolution of dye molecules throughout the monomer matrix before polymerization. This uniform local distribution at the microscopic level prevents concentration gradients that would drive dye migration during curing and setting.

Inventive Principle:
Principle #3Local quality

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 solution achieves a translucent, uniformly dyed PMMA bone cement with improved dye stability and non-toxicity, preventing dye migration by incorporating the solubilizer into the polymer chains during radical polymerization, ensuring effective and safe visualization during medical procedures.

Implementation Method 1

0.001-1.00 mass percent of a dye or dye mixture that is insoluble or poorly soluble in methacrylic acid methyl ester and 0.001-2.00 mass percent of a synthetically produced, protein-free, hydrophobic, low-molecular or oligomeric solubilizer for the dye or dye mixture are dissolved in the monomer liquid

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 2

After mixing the monomer component and powder component, the bone cement hardens within a few minutes by radical polymerization of the monomer

Methodology Applied
Scientific EffectRadical polymerization: Photopolymerisation

Data Source

PatentUS7655706B2Polymethylmethacrylate bone cement
Publication Date: 2010.02.02 HERAEUS MEDICAL GMBH

AI summary

A polymethylmethacrylate bone cement with a liquid monomer component and a solid component contains in the monomer liquid, for example, 0.001-1.00 mass percent of a dye or dye mixture that is insoluble or poorly soluble in methacrylic acid methylester and, for example, 0.001-2.00 mass percent of a synthetically produced, protein-free, hydrophobic, low molecular or oligomeric solubilizer for the dye or dye mixture. The solubilizer preferably is liquid or pasty at room temperature. The monomer liquid is translucent at room temperature. Preferably, 0.001-1.00 mass percent of a dye or dye mixture that is insoluble or poorly soluble in methacrylic acid methylester and, preferably, 0.001-2.00 mass percent of a synthetically produced, protein-free, hydrophobic, low molecular or oligomeric solubilizer that is liquid or pasty at room temperature are homogeneously dissolved in the polymethacrylate or polymethylacrylate of the powder component.