Silica Microsphere Manufacturing for SIRT Density Control

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Solution Overview

Problem

Existing microspheres for selective internal radiation therapy (SIRT) face challenges such as high density leading to rapid sedimentation, potential leaching of radioactive yttrium, and difficulties in manufacturing and storage, with current polymer-based and glass-based microspheres each having inherent disadvantages.

Innovation Solution

A method for manufacturing silica microspheres involving the steps of mixing acid and water, adding silicon alkoxide, precipitating, and immersing in acid or alkali, followed by drying and radionuclide infusion, to achieve microspheres with controlled density and yttrium load, ensuring stability and distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If glass-based microspheres (YAS) are used, then chemical durability and yttrium load are improved, but density becomes too high causing rapid sedimentation

Engineering Contradiction:

Improvechemical durabilityVSAvoiddensity

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent uses a composite structure combining glass matrix with porous polymer coating. The glass core provides chemical durability and high yttrium load, while the porous polymer shell reduces overall density to match blood plasma, preventing rapid sedimentation. This composite approach resolves the contradiction between chemical durability and density.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent employs porous polymer microspheres as the carrier structure. The porous structure allows for high surface area and controlled porosity (30-70%) to reduce density while maintaining mechanical integrity. The porous polymer matrix provides a framework that can be infused with radionuclides while keeping the overall sphere density low enough for proper blood flow distribution.

Inventive Principle:

Principle #31Porous materials

2Weight of moving object

If polymer-based microspheres (ion exchange) are used, then density is suitable for SIRT, but radioactive yttrium can be leached under certain conditions

Engineering Contradiction:

ImprovedensityVSAvoidyttrium leaching

Core Design Contradiction:

Weight of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent combines glass-based microspheres (providing chemical durability and stable yttrium bonding) with porous polymer coating (providing suitable density). The glass core strongly bonds yttrium, preventing leaching, while the polymer shell adjusts the overall density to match blood plasma. This composite structure eliminates the leaching problem while maintaining suitable density.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters by using glass-based materials instead of polymer ion exchange resins. The glass matrix provides different chemical properties with stronger bonding, changing the chemical environment to prevent yttrium leaching while maintaining the density characteristics needed for SIRT therapy.

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If high yttrium load is used, then radioactivity increases allowing lower microsphere count, but blood platelet count may be reduced

Engineering Contradiction:

Improveyttrium loadVSAvoidblood platelet reduction

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent uses porous polymer microspheres with controlled porosity (30-70%) to achieve high surface area and high yttrium loading capacity. The porous structure allows extensive surface area for radionuclide binding, enabling high yttrium load without excessive microsphere count, thereby reducing the risk of blood platelet reduction while maintaining therapeutic efficacy.

Inventive Principle:

Principle #31Porous materials

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 produces microspheres with a lower density and controlled yttrium load, reducing the risk of sedimentation and leaching, while allowing for efficient distribution and reuse, thereby improving the efficacy and safety of SIRT therapy.

Implementation Method 1

adding a silicon alkoxide to the mixture so as to precipitate microspheres

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

adding a silicon alkoxide to the mixture so as to precipitate microspheres

Methodology Applied

Scientific EffectCondensation:

Implementation Method 3

allowing the microspheres to settle into a sediment and removing a supernatant liquid

Methodology Applied

Scientific EffectSedimentation: Sedimentation

Implementation Method 4

immersing the microspheres in acid

Methodology Applied

Scientific EffectChemical etching:

Implementation Method 5

infusing a radionuclide into the microspheres

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 6

infusing a radionuclide into the microspheres

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS20230050728A1Method of manufacturing silica microspheres

Publication Date: 2023.02.16 GRAG TECH PTY LTD

AI summary

There is provided a method of manufacturing silica microspheres includes the steps of mixing acid and water to form a mixture; adding a silicon alkoxide to the mixture so as to precipitate microspheres; allowing the microspheres to settle into a sediment and removing a supernatant liquid; and immersing the microspheres in acid.