Lanthanide Complexes for NIR Imaging Autofluorescence
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Solution Overview
Problem
Current lanthanide complexes used for NIR imaging face challenges due to weak NIR signals being masked by autofluorescence, necessitating the development of complexes with long decay times and improved luminescence properties.
Innovation Solution
The use of polydentate ligands derived from molecules like 2-(2′-hydroxyphenyl)benzene-fused azole compounds, such as 2-(2′-hydroxyphenyl)benzoxazole (HBO), 2-(2′-hydroxyphenyl)benzothiazole (HBT), and 2-(2′-hydroxyphenyl)benzimidazole (HBI), which form stable complexes with lanthanide ions, enhancing energy transfer and NIR signal intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fluorescent probes are used for NIR imaging, then imaging can be performed, but the weak NIR signals are masked by autofluorescence from biological materials
Solution Approach 1:
The patent changes the emission wavelength parameter by using lanthanide ions (particularly Nd3+, Er3+, Tm3+, and Yb3+) that emit in the deep NIR region (880-1100 nm), where biological autofluorescence is minimal. This parameter change shifts the operating wavelength away from the harmful autofluorescence region, enabling clear signal detection.
Solution Approach 2:
The patent introduces organic ligands (such as porphyrins, phthalocyanines, and other chromophores) as intermediary molecules that absorb visible light and transfer energy to the lanthanide ions. These ligands act as antennas that capture energy efficiently and transfer it to the lanthanide, which then emits NIR light, thereby mediating the energy transfer process and enhancing the overall luminescence efficiency.
2Object-affected harmful factors
If luminescent probes with long emission wavelengths are developed to overcome autofluorescence, then background noise is reduced, but the signal intensity and quantum yield must be sufficiently high for effective imaging
Solution Approach 1:
The patent creates composite luminescent systems combining organic ligands with lanthanide ions. The organic ligands provide strong absorption and energy transfer capabilities, while the lanthanide ions provide long-lived NIR emission. This composite approach synergistically combines the advantages of both components to achieve high brightness and long wavelength emission simultaneously.
Solution Approach 2:
The patent utilizes the long excited state lifetime of lanthanide ions (milliseconds to microseconds) compared to conventional fluorophores (nanoseconds). This continuous emission over extended time periods allows for time-gated detection methods that can further suppress autofluorescence while maintaining high signal intensity, effectively extending the useful action of the luminescent probe.
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
These complexes exhibit improved sensitization capacity and increased NIR signal intensity, allowing for more efficient detection and imaging applications, including early disease detection and treatment monitoring.
Implementation Method 1
enhancing energy transfer and NIR signal intensity
Implementation Method 2
complexes that absorb or fluoresce in the visible or near-infrared (NIR) region
Implementation Method 3
Fluorescent molecules that absorb and emit light in the near-infrared (NIR) region
Data Source
AI summary
A lanthanide complex, method of forming and method of using the lanthanide complex as a near-infrared luminescent material are described. The complex includes at least one lanthanide ion and at least one polydentate ligand derived from a molecule having the general formula of Structure 2:where: E represents a heteroatom or heteroatom-containing group and R1-R8 are independently selected from H, —OH, —NH2, —SO3H, —CO2H, halides, optionally substituted organic groups; and conjugated linking groups which link two of the polydentate ligands of Structure 2 together.