Tri-Doped Upconverting Nanoparticles 800 nm Excitation
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Solution Overview
Problem
Upconverting nanoparticles (UCNPs) face limitations due to their physically unalterable excitation band centered at 980 nm, which overlaps with water absorption, causing heating issues in biological systems, and existing methods for modifying excitation are limited, especially for applications requiring deep tissue imaging or high power density.
Innovation Solution
Development of tri-doped UCNPs with a constitutional excitation peak at 800 nm, utilizing Nd3+ as a photon sensitizer and Yb3+ as bridging ions, enabling strong green or blue upconversion emissions without photobleaching, and employing a core/shell or core/shell/shell architecture to optimize energy transfer and reduce surface quenching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If Yb3+-sensitized UCNPs are used for upconverting luminescence, then strong upconversion emission is achieved, but the excitation band at 980 nm overlaps with water absorption causing heating damage in biological systems
Solution Approach 1:
The patent changes the excitation wavelength parameter from 980 nm to 800 nm by introducing Nd3+ as a sensitizer. This parameter change moves the excitation band away from the water absorption peak at 980 nm to a region with minimal water absorption at 800 nm, thereby reducing heating damage while maintaining strong upconversion emission through the Nd3+-Yb3+ energy transfer mechanism
Solution Approach 2:
The patent introduces Nd3+ ions as an intermediary sensitizer that absorbs 800 nm light and transfers energy to Yb3+ ions, which then transfer to the emitting lanthanide ions. This intermediary mechanism allows excitation at 800 nm (away from water absorption) while still achieving strong upconversion emission through the Nd3+→Yb3+→Ln3+ energy transfer chain
2Measurement precision
If higher power density is used to enhance upconversion signal for deep tissue imaging, then imaging depth is improved, but heating effect on tissues becomes more severe
Solution Approach 1:
The patent changes the excitation wavelength from 980 nm to 800 nm, exploiting the fact that 800 nm is in the optical window with minimal water absorption. This allows deeper tissue penetration and enhanced signal detection without requiring high power density, thereby improving imaging depth while avoiding severe heating effects
3Illumination intensity
If conventional dyes or quantum dots are used for imaging, then high brightness is achieved, but photobleaching occurs limiting long-term applications
Solution Approach 1:
The patent uses a composite nanoparticle system containing multiple lanthanide ions (Nd3+, Yb3+, and emitting Ln3+ such as Er3+ or Tm3+) embedded in an inorganic host matrix. This composite inorganic structure provides both high upconversion emission brightness and exceptional photostability, eliminating photobleaching while maintaining strong signal for long-term imaging applications
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 tri-doped UCNPs achieve a 20-fold enhancement in upconversion emission yield at 800 nm excitation, maintaining biocompatibility and avoiding photo-bleaching, allowing for efficient use in biological applications such as imaging and sensing with minimal tissue heating.
Implementation Method 1
employing a constitutional excitation peak at 800 nm that utilizes Nd3+ as a photon sensitizer and Yb3+ as bridging ions
Implementation Method 2
Yb3+ as bridging ions, affording strong green or blue upconversion emissions
Implementation Method 3
Upconverting luminescence refers to an anti-Stokes type process in which the sequential absorption of two or more photons leads to the emission of light at shorter wavelength
Implementation Method 4
employing a core/shell or core/shell/shell architecture to optimize energy transfer and reduce surface quenching
Data Source
AI summary
The invention generally relates to materials and methods for creating and/or utilizing upconverting luminescence. More particularly, the invention relates to novel compositions (e.g., nanoparticles) and related methods of preparation and use that enable upconverting luminescence with an efficient excitation optimized at about 800 nm. A unique class of cascade sensitized tri-doped UCNPs with a biocompatible 800 nm excitable property are disclosed herein, for example, tri-doped β-NaYF4:Nd,Yb,Er(Tm)/NaYF4 UCNPs, which employ Nd3+ as 800 nm photon sensitizer and Yb3+ as bridging ions, having strong green or blue upconversion emissions without photobleaching.