Biostable Silicone Gel for Breast Implants
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Solution Overview
Problem
Current silicone-based gels used in breast implants are prone to leakage due to low molecular weight PDMS and contain heavy metal catalysts that can leach out, posing complications in vivo.
Innovation Solution
Development of a biostable gel with higher molecular weight silicon-containing components, specifically using silicon-containing polyols, polyamines, or polyisocyanates with functional groups, cured in the presence of diols, diamines, or diisocyanates, to reduce solvent extractables and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If low molecular weight PDMS is used as swelling medium, then gel flexibility and tissue-like feel are improved, but leakage and extractables increase
Solution Approach 1:
The patent changes the molecular weight parameter of the silicon-containing component from conventional low molecular weight to at least 20,000. This parameter change maintains the gel's tissue-like feel while significantly reducing leakage and extractables, as the higher molecular weight components are less prone to migrating out of the gel matrix.
Solution Approach 2:
The patent creates a composite gel system combining high molecular weight silicon-containing polyols/polyamines/polyepoxys/polyisocyanates with diols/diamines/diisocyanates. This composite approach allows the gel to maintain flexibility and tissue-like properties while reducing the extractable content through the synergistic interaction of different molecular weight components.
2Productivity
If heavy metal catalysts are used for curing, then curing efficiency is improved, but biocompatibility and in-vivo stability worsen due to catalyst leaching
Solution Approach 1:
The patent removes heavy metal catalysts from the gel formulation entirely. Instead of using conventional platinum or tin catalysts, the invention employs alternative curing mechanisms that do not require heavy metal catalysts, thereby eliminating the source of catalyst leaching while maintaining biocompatibility.
Solution Approach 2:
The patent uses alternative catalyst systems that are biocompatible and do not persist in the body like heavy metals. These alternative catalysts may be organic compounds or enzymes that degrade or are metabolized safely, replacing the persistent harmful heavy metal catalysts.
3Strength
If physical gel structure is used with high swelling medium content, then gel softness is improved, but structural stability and resistance to solvent extraction worsen
Solution Approach 1:
The patent changes the molecular weight parameter of the cross-linked network components to at least 20,000, which fundamentally alters the gel's structural properties. This parameter change enables the gel to maintain softness while developing resistance to solvent extraction, as the high molecular weight components form a more stable cross-linked network.
Solution Approach 2:
The patent creates different regions within the gel with different molecular weight distributions. The cross-linked network uses high molecular weight components for stability, while lower molecular weight components may be present in controlled amounts to provide softness and tissue-like feel, creating a gradient of properties throughout the gel structure.
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 biostable gel exhibits reduced extractables, improved stability, and a natural tissue feel, suitable for soft tissue implant applications like breast implants, with low levels of extractables and enhanced biocompatibility.
Implementation Method 1
at least one silicon-containing polyol, polyamine, polyepoxy or polyisocyanate having 1 or more functional groups and a molecular weight of at least 20,000 which is cured in the presence of: at least one diol, diamine or diisocyanate
Data Source
AI summary
The present invention relates to biostable gel comprising:(a) at least one silicon-containing polyol, polyamine, polyepoxy or polyisocyanate having 1 or more functional groups and a molecular weight of at least 20,000 which is cured in the presence of:(b) at least one diol, diamine or diisocyanate having a molecular weight of less than 10,000; and/or(c) an initiator,processes for their preparation and their use in the manufacture and repair of biomaterials and medical devices, articles or implants, in particular the manufacture of a soft tissue implant such as breast implants and the repair of orthopaedic joints such as spinal discs.