Ambient-Cure Silicone Foam for Injectable Implants
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Solution Overview
Problem
Current silicone gel formulations for implant devices are highly viscous, making them non-injectable and unable to be adjusted post-implantation, and thermal curing is not compatible with implanted devices, leading to undesirable effects.
Innovation Solution
A two-part RCSF composition comprising a catalyst fluid and a cross-linker suspension, which can be mixed to form an injectable composition with low viscosity, allowing for in situ cross-linking and gelation within an implanted medical device, enabling adjustable volume and defect-free filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional silicone gel formulations are used for implant devices, then the implant provides structural stability, but the gel is highly viscous and cannot be injected or adjusted post-implantation
Solution Approach 1:
The silicone gel is divided into two separate components (catalyst component and crosslinker component) that are stored separately and mixed only at the time of use. This segmentation allows each component to maintain low viscosity independently, enabling injectability, while the crosslinking reaction after mixing provides the desired structural stability.
Solution Approach 2:
The patent changes the chemical parameters of the silicone formulation by using specific vinyl-functional and hydride-functional siloxane polymers with controlled molecular weights and viscosities (5-500 cSt). The catalyst component contains platinum at 1-100 ppm, and the crosslinker component contains controlled amounts of crosslinking agents, allowing the mixture to achieve optimal injectability and subsequent gelation properties.
2Reliability
If thermal curing is used for silicone gel, then the gel achieves full curing and stability, but the process causes expansion and contraction of foam-forming gas resulting in undesirable effects on form and shape
Solution Approach 1:
The patent replaces the thermal curing process with a chemical crosslinking reaction that occurs at ambient temperature. The platinum catalyst facilitates the crosslinking between vinyl-functional and hydride-functional siloxane groups without requiring external heating, thereby eliminating thermal expansion and contraction of the foam-forming gas while achieving complete curing.
Solution Approach 2:
The curing process parameters are changed from thermal (high temperature) to chemical (ambient temperature with catalyst). The crosslinking reaction is initiated by mixing the catalyst component containing platinum with the crosslinker component, allowing the gel to cure at body temperature without the harmful thermal effects on foam structure.
3Adaptability or versatility
If current silicone foam compositions are used, then the implant contains gas-filled microbubbles for volume adjustment, but thermal curing causes expansion and contraction resulting in defective gel formation
Solution Approach 1:
The patent replaces thermal curing with chemical crosslinking at ambient temperature, eliminating the thermal expansion and contraction that causes defective gel formation in foam structures. This allows the gas-filled microbubbles to remain stable during the curing process while the gel matrix forms uniformly around them.
Solution Approach 2:
The patent creates a composite material system combining the silicone gel matrix with gas-filled microbubbles or foam-forming agents. The chemical crosslinking process at ambient temperature allows this composite structure to form properly, maintaining both the gel's structural integrity and the gas pockets' volume stability for post-implantation adjustment.
4Strength
If highly viscous silicone gel is used, then the implant provides sufficient structural support, but the gel cannot be injected via hypodermic needle for in situ filling
Solution Approach 1:
The silicone gel is segmented into two low-viscosity components that can be easily injected separately through hypodermic needles. After injection, the components mix and crosslink to form the high-strength gel structure, providing structural support without compromising injectability.
Solution Approach 2:
The patent carefully selects siloxane polymers with viscosities of 5-500 cSt for both catalyst and crosslinker components, ensuring they remain fluid enough for injection. The crosslinking reaction then transforms these low-viscosity liquids into a high-strength gel with viscosity >100,000 cPs, achieving both injectability and structural support.
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 RCSF composition allows for the adjustment of implant volume and defect-free filling of implanted medical devices, providing a consistent gel properties similar to conventional silicone gel and preventing leakage, with a fully cured viscosity exceeding 50,000 cPs within specified timeframes.
Implementation Method 1
a catalyst component comprising a platinum catalyst and a vinyl functional siloxane polymer, and a crosslinker component comprising a hydride functional siloxane polymer, wherein the vinyl functional siloxane polymer and the hydride functional siloxane polymer crosslink in the presence of the platinum catalyst
Implementation Method 2
The RCSF composition may further comprise a foam-forming agent, and wherein the foam-forming agent comprises from about 5 vol % to about 50 vol % of the total volume of the RCSF composition
Data Source
AI summary
Provided are rapidly cross-linkable silicone foam compositions, kits, and methods for filling implanted medical devices in situ or in vivo, the implanted medical devices, including for example, body implants and tissue expanders, the compositions including a platinum divinyl disiloxane complex; a low viscosity vinyl terminated polydimethylsiloxane; a low viscosity hydride terminated polydimethylsiloxane; a silicone cross-linker; and a gas and/or gas-filled microcapsules, where the rapidly cross-linkable silicone foam composition has a viscosity of ≤150 cPs for ≥1 min. post-preparation and ≤300 cPs≤5 min. post-preparation, at ambient temperature.