Functionalized PEGylated Nanoparticles With Sub-10 nm Size Control
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Solution Overview
Problem
Current methods for synthesizing ultrasmall silica nanoparticles face challenges in achieving size control, monodispersity, and efficient incorporation of functional groups, particularly for near-infrared emitting dyes, which are crucial for therapeutic and diagnostic applications, due to limitations in existing synthesis processes and surface modification techniques.
Innovation Solution
A post-PEGylation surface modification by insertion (PPSMI) approach is employed, allowing for the aqueous synthesis of ultrasmall core-shell silica nanoparticles with improved size control and functionalization, enabling the integration of multiple functional ligands such as fluorescence, targeting, and therapeutic agents, using amine- and thiol-functionalized silanes in a one-pot water-based process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the Stöber process is used to synthesize silica nanoparticles, then particles can be produced with diameters from tens of nm to microns, but particle sizes of 10 nm and below are at the limit of size control due to reaction kinetics limitations in alcohol
Solution Approach 1:
The patent changes the solvent parameter from alcohol to water, and adjusts pH conditions to achieve precise size control below 10 nm. This parameter change overcomes the reaction kinetics limitations of the traditional Stöber process while maintaining synthesis feasibility.
Solution Approach 2:
The synthesis process is segmented into distinct stages: nucleation, growth, and surface modification. This segmentation allows independent optimization of each stage, enabling precise size control while maintaining process versatility.
2Stability of the object's composition
If silica particle surfaces are covalently covered with PEG, then particle stability is improved, but loss of surface charge during PEGylation may result in particle aggregation or broadening of particle size distribution
Solution Approach 1:
The patent performs preliminary surface charge stabilization before PEGylation by controlling the silica surface chemistry. This preliminary action prevents charge loss during subsequent PEGylation, avoiding aggregation and maintaining narrow size distribution.
Solution Approach 2:
The patent uses silane coupling agents as intermediaries between the silica surface and PEG chains. These intermediaries maintain surface charge while enabling stable PEG attachment, preventing direct charge loss that would cause aggregation.
3Adaptability or versatility
If covalent encapsulation of silane-conjugated organic fluorescent dyes with negatively charged groups is performed into SNPs, then fluorescence functionality is achieved, but encapsulation efficiencies are low due to electrostatic repulsion between silica and fluorophore
Solution Approach 1:
The patent inverts the traditional encapsulation approach by first functionalizing the silica surface with positive charge groups, then introducing negatively charged fluorophores. This reversal of charge sequence eliminates electrostatic repulsion and enables high encapsulation efficiency.
Solution Approach 2:
The patent changes the surface charge parameter of silica from negative to positive through chemical modification. This parameter change eliminates electrostatic repulsion with negatively charged fluorophores, dramatically improving encapsulation efficiency while maintaining fluorescence functionality.
4Reliability
If ultrasmall inorganic nanoparticles are synthesized for renal clearance, then efficient clearance from the body is achieved, but synthesis and cleaning protocols are complex when using alcohol as solvent
Solution Approach 1:
The patent replaces expensive and hazardous alcohol solvents with water, a cheap and benign alternative. This substitution simplifies synthesis and cleaning protocols while maintaining the production of ultrasmall nanoparticles suitable for renal clearance.
Solution Approach 2:
The patent changes the solvent parameter from alcohol to water, which fundamentally simplifies the synthesis and purification protocols. Water-based synthesis eliminates volatile organic compound handling and simplifies cleaning procedures while producing nanoparticles with identical renal clearance properties.
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
This method achieves precise control over particle size, distribution, and functionalization, resulting in nanoparticles suitable for clinical applications, with enhanced fluorescence, targeting, and therapeutic capabilities, overcoming previous synthesis limitations.
Implementation Method 1
contacting a nanoparticle... with one or more functionalizing precursor comprising at least one reactive group, where a functionalized nanoparticle comprising at least one reactive group covalently bound to a surface of the functionalized nanoparticle is formed
Implementation Method 2
using amine- and thiol-functionalized silanes in a one-pot water-based process
Data Source
AI summary
Described is a versatile surface modification approach to, for example, modularly and orthogonally functionalize nanoparticles (NPs) such as, for example, PEGylated nanoparticles, ith various types of different functional ligands (functional groups) on the NP surface. It enables the synthesis of, for example, penta-functional PEGylated nanoparticles integrating a variety of properties into a single NP, e.g., fluorescence detection, specific cell targeting, radioisotope chelating/labeling, ratiometric pH sensing, and drug delivery, while the overall NP size remains, for example, below 10 nm.