Gold Nanoparticle Surface Coating for Stable Light-Filtering Hydrogels
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Solution Overview
Problem
Existing methods for integrating gold nanoparticles into hydrogels for light filtering applications lack stability, versatility, and tunability, particularly under thermal and mechanical stress, and are limited by the high surface energy of anisotropic nanoparticles, which leads to thermal reshaping and instability.
Innovation Solution
A composition comprising gold nanoparticles coated with poly(vinylpyrrolidone) and anchored with thiolated methacrylate dimers, such as bis(2-methacryloyl)oxyethyl disulfide, to enhance stability and integration into hydrogels, allowing for selective light filtering and resistance to autoclaving and UV exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gold nanoparticles are integrated into hydrogels using conventional methods (citrate coating), then the nanoparticles can be dispersed in the hydrogel, but the nanoparticles exhibit poor stability and leaching under thermal and mechanical stress
Solution Approach 1:
The patent uses a composite coating system combining poly(vinylpyrrolidone) (PVP) and thiolated methacrylate dimers on gold nanoparticle surfaces. This composite approach leverages the steric stabilization from PVP and the covalent anchoring from thiolated methacrylate dimers, creating a multi-functional coating that provides both colloidal stability and resistance to leaching under stress conditions.
Solution Approach 2:
The thiolated methacrylate dimers act as intermediary molecules that bridge the gold nanoparticle surface and the hydrogel matrix. These intermediaries form covalent bonds with both the nanoparticle surface (via thiol-gold interaction) and the hydrogel network (via methacrylate polymerization), effectively anchoring the nanoparticles and preventing leaching.
2Adaptability or versatility
If anisotropic gold nanoparticles are used for light filtering applications, then versatile and tunable optical properties are achieved, but the high surface energy causes thermal reshaping and instability
Solution Approach 1:
The patent applies surface modification with PVP and thiolated methacrylate dimers before the nanoparticles are exposed to thermal stress during hydrogel processing (autoclaving). This preliminary coating action reduces the surface energy of the anisotropic nanoparticles in advance, preventing thermal reshaping when the nanoparticles are subsequently subjected to high temperatures.
Solution Approach 2:
The patent changes the surface energy parameter of the anisotropic gold nanoparticles by coating them with PVP and thiolated methacrylate dimers. This parameter change reduces the driving force for thermal reshaping while preserving the anisotropic shape and associated optical properties, enabling both versatility and thermal stability.
3Ease of manufacture
If gold nanoparticles are added to contact lenses after curing, then the manufacturing process is simple, but the nanoparticle distribution is non-uniform and integration is poor
Solution Approach 1:
The patent performs preliminary surface functionalization of the gold nanoparticles with thiolated methacrylate dimers before lens manufacturing. This preliminary action enables the nanoparticles to be incorporated into the hydrogel monomer mixture prior to curing, where they will be uniformly distributed as the hydrogel network forms around them, achieving both good distribution and relatively simple manufacturing.
4Reliability
If high graft density of polymers is used to stabilize gold nanoparticles, then colloidal stability is improved, but the complexity of surface chemistry tailoring increases significantly
Solution Approach 1:
The patent uses thiolated methacrylate dimers as intermediary molecules that provide stable anchoring to the gold nanoparticle surface through thiol-gold bonds, eliminating the need for high polymer graft densities. This intermediary approach achieves colloidal stability through covalent bonding rather than relying on dense polymer brushes, thereby reducing surface chemistry complexity.
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 composition achieves long-term colloidal stability and integration of gold nanoparticles into hydrogels, maintaining optical properties and preventing leaching under stress conditions, enabling versatile light filtering across specific wavelengths.
Implementation Method 1
These compounds stabilize the nanoparticles as colloidal suspensions via either steric or electrostatic interactions.
Implementation Method 2
an anchoring mechanism disposed to promote chemical conjugation of at least a portion of the plurality of gold nanoparticles to the base material
Implementation Method 3
the composition exhibits a peak light filtering value in the range of about 600 nm to about 1000 nm
Data Source
AI summary
A composition for light filtering, the composition comprising a base material; a plurality of metal nanoparticles dispersed in the base material; a stabilizing mechanism disposed to selectively couple with at least a portion of the plurality of metal nanoparticles to enhance stability of at least the portion of the plurality of metal nanoparticles in the base material; and an anchoring mechanism disposed to promote chemical conjugation of at least a portion of the plurality of metal nanoparticles to the base material, wherein the composition exhibits a peak light filtering value in the range of about 600 nm to about 1000 nm, and wherein the composition exhibits a filtering spectrum having a full width at half maximum of about 58 nm-70 nm.