Plasmonic Nanostructures for NIR-II Fluorescence Enhancement
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Solution Overview
Problem
Current NIR-II and NIR-III dyes have low quantum yields, limiting their biomedical applications, particularly in cancer surgery where accurate differentiation between cancerous and healthy tissue is crucial, due to low fluorescence intensity and the need for large dye amounts to achieve sufficient imaging.
Innovation Solution
Nanostructures comprising a dielectric core with a metallic plasmonic coating, specifically designed to enhance fluorescence in the NIR-II and NIR-III regions through metal-enhanced fluorescence (MEF), using emitters like fluorescent dyes or quantum dots, which increase fluorescence intensity by optimizing spectral overlap and spacing between the emitter and the plasmonic nanoparticle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If current NIR-II and NIR-III dyes are used for fluorescence imaging, then imaging can be performed in the NIR-II and NIR-III windows with lower optical scattering and autofluorescence, but the quantum yield is low resulting in insufficient fluorescence intensity
Solution Approach 1:
The patent combines a fluorophore (emitter) with a plasmonic nanoparticle to create a composite nanostructure. The plasmonic nanoparticle enhances the fluorescence emission of the fluorophore through localized surface plasmon resonance, thereby increasing the quantum yield and fluorescence intensity in the NIR-II and NIR-III windows without requiring larger dye amounts
Solution Approach 2:
The patent optimizes spectral parameters by tuning the plasmon resonance frequency of the nanoparticle to match the emission spectrum of the fluorophore. This spectral overlap optimization maximizes the enhancement effect, converting the harmful low quantum yield into high fluorescence intensity through parameter matching
2Illumination intensity
If a large amount of dye is used to compensate for low quantum efficiency, then sufficient fluorescence signal can be achieved, but this is not physiologically appropriate and may cause toxicity
Solution Approach 1:
The plasmonic nanoparticle acts as an intermediary that amplifies the fluorescence signal of a small amount of fluorophore. Instead of using large amounts of dye directly, the nanoparticle mediates the light-matter interaction to achieve signal amplification, thereby reducing the required dye concentration to physiologically safe levels
Solution Approach 2:
The patent replaces the mechanical approach of increasing dye concentration with an optical field enhancement mechanism. The plasmonic nanoparticle creates localized electromagnetic field enhancement that substitutes for the need to increase fluorophore quantity, reducing phototoxicity while maintaining signal brightness
3Illumination intensity
If visible radiation is used for fluorescence excitation, then molecular energy levels can be excited, but optical scattering and autofluorescence background swamp the fluorescence signals
Solution Approach 1:
The patent changes the excitation wavelength parameter from visible to NIR-II/NIR-III range. This parameter change exploits the biological transparency window where water and biological tissues have lower absorption, reducing optical scattering and autofluorescence background while maintaining effective fluorescence excitation through the plasmon-enhanced fluorophore
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
Significantly enhances fluorescence intensity in the NIR-II and NIR-III regions, allowing for more accurate real-time bioimaging during surgery with reduced dye amounts, improving tissue differentiation and surgical precision.
Implementation Method 1
The enhanced fluorescence occurs through metal enhanced fluorescence (MEF). This is an optical process whereby, through the interaction between an emitter such as a fluorophore and a plasmonic nanoparticle (usually gold or silver) under specific conditions, an increase in the fluorescence intensity of the emitter, for example the fluorophore, can be observed
Implementation Method 2
The magnitude of such enhancement is highly dependent on a number of factors, one of which being the spectral overlap between the localised surface plasmon resonance (LSPR) of the metal nanoparticle and the absorption and emission of the emitter
Data Source
AI summary
The present invention provides compositions and methods for enhancing fluorescence from emitters that emit in the NIR-II and NIR-III. The compositions have particular use in both in vitro diagnostics, and in the live imaging of tissue during surgery, for example during removal of a tumour.