NIR-II Organic Fluorescent Probe for White-Light Vascular Imaging
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Solution Overview
Problem
NIR-II organic fluorescent molecules require expensive lasers for excitation due to low quantum yield and molar extinction coefficient, leading to limited photon absorption, laser-induced biological damage, and uneven irradiation, hindering their use in high-performance in vivo fluorescence imaging.
Innovation Solution
Development of a second near-infrared (NIR-II) organic fluorescent probe with an A-D-A structure, synthesized via a one-step Knoevenagel reaction, which is excited by white light, mixed with an organic coating agent to form nanoparticles with high quantum yield and molar extinction coefficient, enabling bright NIR-II fluorescence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If expensive lasers with specific wavelengths are used to excite NIR-II organic fluorescent molecules, then imaging sensitivity is improved, but cost increases and laser-induced biological damage occurs
Solution Approach 1:
The patent replaces expensive, complex laser systems with inexpensive, readily available white light sources (such as LEDs or lamps) to excite the fluorescent probe. This substitution eliminates the harmful effects of lasers while maintaining imaging capability, directly addressing the contradiction between imaging sensitivity and biological safety
Solution Approach 2:
The invention changes the excitation wavelength parameter from specific narrow-band laser wavelengths to broad-spectrum white light wavelengths. The probe is designed with an absorption spectrum that covers the visible range (400-800 nm), allowing excitation by multiple wavelengths simultaneously, thereby achieving both cost reduction and elimination of laser-induced damage
2Use of energy by moving object
If single-wavelength lasers are used for excitation, then specific absorption is improved, but photon absorption is limited and irradiation becomes uneven
Solution Approach 1:
The fluorescent probe is designed with multi-functional absorption characteristics, capable of absorbing photons across a broad wavelength range (400-800 nm) simultaneously. This allows a single white light source to provide uniform excitation across the entire field of view, eliminating the uneven irradiation problem associated with single-wavelength lasers while maximizing photon absorption efficiency
Solution Approach 2:
The invention transitions from one-dimensional (single wavelength) laser excitation to three-dimensional (broad spectrum) white light excitation. The probe's absorption spectrum spans multiple wavelengths, enabling simultaneous excitation at different wavelengths across the sample, thereby achieving uniform irradiation and improved energy utilization
3Length of stationary object
If NIR-II organic fluorescent molecules are used, then tissue penetration depth is improved, but quantum yield and molar extinction coefficient are low
Solution Approach 1:
The patent employs a composite molecular structure consisting of electron-donating groups (such as carbazole or triphenylamine), electron-accepting groups (such as cyanoindanone or difluoroborocyclopentadienone), and connecting units. This composite design creates a push-pull electronic structure that simultaneously extends the absorption and emission spectra into the NIR-II region while maintaining high quantum yield and molar extinction coefficient, thereby resolving the contradiction between penetration depth and luminous efficiency
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 fluorescent probe achieves high-resolution imaging of blood vessels under white light excitation, avoiding laser-induced damage and uneven irradiation, suitable for non-therapeutic in vivo imaging and image-guided surgery.
Implementation Method 1
a second near-infrared (NIR-II) organic fluorescent probe... excited by white light... bright second near-infrared fluorescence
Data Source
AI summary
Provided are a second near infrared organic fluorescent probe, a preparation method and use thereof. The fluorescent probes is mixed with an organic coating agent to prepare a nanoimaging agent. The nanoimaging agents have a high molar extinction coefficient and a high quantum yield, and exhibit bright NIR-II fluorescence under excitation of white light. Furthermore, the nanoimaging agents could achieve high-resolution imaging of blood vessels under excitation of white light. In addition, using white light as excitation light source in the imaging process could effectively avoid problems caused by single wavelength excitation light source, such as limited photon absorption, laser-induced biological damage, and uneven irradiation. Moreover, laser light source is high in cost, while white light source is low in cost and easily available. The second near infrared organic fluorescent probe may be synthesized by a one-step Knoevenagel reaction without any metal catalysis.