NIR-II Fluorescent Composite for Deep Tissue Imaging
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Solution Overview
Problem
Current near-infrared (NIR) imaging technologies face limitations due to the instability and short half-life of widely used contrast agents like indocyanine green (ICG), which are sensitive to solvents and excitation conditions, and have limited injection depth, while X-ray radiography is restricted by radiation dose limits.
Innovation Solution
A near-infrared-II (NIR-II) fluorescent composite is developed, comprising a gold nanocluster with thiol-based compounds on its surface encapsulated by a capping layer of alpha-glycerylphosphorylcholine (alpha-GPC), which shifts the emission wavelength to 900-1700 nm, enabling deeper tissue imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If indocyanine green (ICG) is used as a contrast agent for NIR imaging, then imaging capability is achieved, but stability is poor and half-life is short
Solution Approach 1:
The patent uses composite materials by combining gold nanoclusters with capping agents (such as thiols, peptides, or polymers) to create a stable NIR-II fluorescent composite. This composite structure protects the gold nanocluster core while providing functional properties, resolving the instability issue of single-material contrast agents like ICG.
Solution Approach 2:
The patent changes the emission wavelength parameter from NIR-I (700-900 nm) to NIR-II (1000-1700 nm) by adjusting the gold nanocluster size and composition. This parameter change enables deeper tissue penetration and reduced scattering, improving both stability and duration of action for imaging applications.
2Ease of operation
If X-ray radiography is used for real-time imaging during surgery, then imaging capability is achieved, but radiation dose exposure increases
Solution Approach 1:
The patent replaces the mechanical/radiation-based X-ray imaging system with an optical fluorescence imaging system using gold nanoclusters. This substitution eliminates ionizing radiation exposure while maintaining real-time imaging capability during surgical procedures through NIR-II fluorescence detection.
3Reliability
If NIR-I imaging with ICG is used, then imaging capability is achieved, but injection depth is limited
Solution Approach 1:
The patent changes the wavelength parameter from NIR-I (700-900 nm) to NIR-II (1000-1700 nm) by adjusting gold nanocluster properties. This parameter change enables deeper tissue penetration because NIR-II light experiences reduced scattering and absorption in biological tissues, directly increasing the effective injection depth for imaging.
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 NIR-II fluorescent composite provides stable and prolonged emission in the second near-infrared range, enhancing imaging depth and resolution, suitable for bioimaging applications, and is administered in a range of 0.01 to 300 mg/kg for effective tissue contrast.
Implementation Method 1
near-infrared-II (NIR-II) fluorescent composite comprising a gold nanocluster and a capping layer... the NIR-II fluorescent composite has an emission wavelength between 900 to 1700 nm
Data Source
AI summary
Disclosed herein are second near-infrared (NIR-II) fluorescent composite and its production method. The method mainly includes the steps of, mixing a gold nanocluster having a plurality of a thiol-based compound on its outer surface and alpha-glycerylphosphorylcholine (alpha-GPC) in a solvent to form a mixture; replacing the solvent with an inert gas; and heating the mixture at a temperature about 100-200° C. in the presence of the inert gas until at least a portion of the gold nanocluster is encapsulated by a capping layer consisting of alpha-GPC, thereby producing the NIR-II fluorescent composite. The thus-produced NIR-II fluorescent composite is characterized by having an emission wavelength covering NIR-II region detectable by specialized camera. Also encompassed in the present disclosure is a method for conducting in vivo bioimaging of a target area in a subject. The method includes administering the present NIR-II fluorescent composite to the target area; and detecting the fluorescence emitted therefrom at a wavelength between 900 to 1700 nm.