Dense Silica Shell Nanoparticles for Biocompatible Photoluminescence
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Solution Overview
Problem
Current photoluminescent products lack desirable quantum yield and have toxic heavy metal content, making them unsuitable for biological applications even when encapsulated in silica.
Innovation Solution
Core-shell silica nanoparticles are produced by combining silica precursors with light-absorbing or light-emitting materials under specific hydrolyzing conditions, forming a dense silica shell that enhances photophysical properties such as brightness and stability, using methods like sequential addition of silica precursors at elevated temperatures or pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quantum dots with heavy metal content are used to achieve high quantum yield, then photoluminescent performance is improved, but toxicity increases making them unsuitable for biological applications
Solution Approach 1:
The invention extracts and eliminates the harmful heavy metal content from quantum dots while retaining the photoluminescent functionality. This is achieved by replacing heavy metal-based quantum dots with organic dye-loaded silica nanoparticles that provide comparable quantum yield without the toxic heavy metal components, thus resolving the contradiction between high quantum yield and low toxicity
Solution Approach 2:
The invention uses composite materials by combining organic dyes with silica nanoparticle matrices. This composite structure provides both the desired photoluminescent properties (high quantum yield) and biocompatibility (low toxicity), as the organic dye molecules are encapsulated within the biologically safe silica framework, eliminating the need for toxic heavy metals
2Reliability
If silica shell density is increased to improve photostability and reduce solvent diffusion, then brightness and stability are enhanced, but manufacturing complexity increases due to controlled addition requirements
Solution Approach 1:
The invention segments the silica shell formation process into controlled sequential additions of silica precursor. By dividing the shell formation into multiple discrete steps with controlled addition rates and intervals, the process achieves dense shell formation and high photostability while maintaining manufacturability through systematic process control rather than requiring overly complex manufacturing procedures
Solution Approach 2:
The invention employs periodic action by adding silica precursor at specific time intervals during shell formation. The controlled periodic addition schedule, with specified waiting periods between additions, allows for dense shell formation that enhances photostability while keeping the manufacturing process organized and manageable through rhythmic, repeatable steps rather than continuous uncontrolled processing
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 resulting nanoparticles exhibit improved brightness and photostability, with increased density reducing solvent diffusion and enhancing light emission, addressing the toxicity and performance issues of existing quantum dots.
Implementation Method 1
combining a silica precursor or silica precursors and silica precursor or silica precursors covalently bound to a light-absorbing material and/or light-emitting material (e.g., fluorescent or phosphorescent materials) (functionalized silica precursor(s)) under hydrolyzing conditions resulting in formation of a silica core
Implementation Method 2
The core-shell silica nanoparticles exhibit a density of at least 1.4 g/cm³... increased density reducing solvent diffusion
Data Source
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AI summary
Provided herein are core-shell silica nanoparticles with a dense silica shell. The nanoparticles have improved properties such as, for example, increased photo luminescence and stability. Also provided are methods for making the nanoparticles.