ICG-Loaded Polymer Nanoparticle Stability via Ionic Interaction
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Solution Overview
Problem
Indocyanine green (ICG)-loaded polymer particles, such as PLGA particles and nanoemulsions, face issues with stability due to leakage and aggregation, leading to decreased molar absorption coefficients over time, and are unable to maintain high ICG concentrations due to hydrophilic and hydrophobic compatibility challenges.
Innovation Solution
A particle composition incorporating a hydrophilic dye with a sulfonate group and a hydrophobic polymer, along with a lipid having a positively charged region, a nicotinic acid derivative, or a thiamine derivative, forms a stable salt-like composition that prevents ICG leakage and enhances absorption, using a solid polymer core for dynamic stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ICG is loaded into PLGA particles or nanoemulsions to increase concentration, then the molar absorption coefficient increases, but the particles become dynamically unstable and ICG leaks over time
Solution Approach 1:
The invention uses a composite material system consisting of a hydrophobic polymer core (PLGA or similar), amphiphilic surfactant layer, and hydrophilic ICG molecules. This composite structure allows ICG to be entrapped at high concentrations within the hydrophobic core while the amphiphilic surfactant layer provides dynamic stability and prevents ICG leakage into the aqueous environment, resolving the contradiction between high ICG concentration and particle stability
2Reliability
If water-soluble ICG is used as contrast agent, then safety is improved, but ICG degrades rapidly in water and cannot be accumulated at measurement sites
Solution Approach 1:
The invention employs a flexible nanoparticle shell structure where ICG is encapsulated within a hydrophobic polymer matrix. This shell protects the water-soluble ICG from rapid degradation in aqueous environments while allowing the particle to be administered safely. The encapsulated ICG can then accumulate at target sites over time, extending its duration of action while maintaining safety
3Quantity of substance
If hydrophobic polymer matrix is used to entrap ICG, then ICG concentration increases, but ICG leakage occurs due to hydrophilic-hydrophobic incompatibility
Solution Approach 1:
The invention introduces an amphiphilic surfactant as an intermediary between the hydrophobic polymer matrix and the hydrophilic ICG molecules. This surfactant has both hydrophobic and hydrophilic regions, allowing it to mediate the interaction between ICG and the polymer matrix. The surfactant layer prevents ICG leakage by providing a transition zone that accommodates both hydrophobic and hydrophilic characteristics, enabling high ICG concentration entrapment without leakage
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 provides a dynamically stable ICG-loaded nanoparticle with a high molar absorbance coefficient, effectively preventing discoloration and maintaining ICG concentration, outperforming previous methods in terms of stability and absorption efficiency.
Implementation Method 1
a particle containing a hydrophilic dye having a sulfonate group and a hydrophobic polymer, wherein the particle further has at least one of a lipid having a positively charged region, a nicotinic acid derivative and a thiamine derivative
Implementation Method 2
a particle containing a hydrophilic dye having a sulfonate group and a hydrophobic polymer
Data Source
AI summary
There is provided an ICG-loaded polymer nanoparticle that is dynamically stable, prevents the leakage of contained ICG and the resulting discoloration, and has a high molar absorbance coefficient. The particle contains a hydrophilic dye having a sulfonate group and a hydrophobic polymer, and the particle further contains at least one of a lipid having a positively charged region, a nicotinic acid derivative and a thiamine derivative.