99mTc-FAPI Dimer Probe Scaffold for Higher Tumor Imaging Contrast
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Solution Overview
Problem
Existing diagnostic probes for fibroblast activation protein-α (FAP) based on 99mTc-SPECT have relatively low tumor intake rates and poor contrast, limiting their effectiveness in tumor imaging.
Innovation Solution
Development of a FAP-targeting dimer compound with a novel skeleton structure, labeled with technetium-99m, utilizing linkers such as aliphatic carbon chains and polyethylene glycol chains, and a nuclide chelating group like 6-hydrazinopyridine-3-carboxylic acid (HYNIC) for enhanced tumor targeting and retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing 99mTc-SPECT diagnostic probes are used for FAP targeting, then the diagnostic probe can be prepared and used for imaging, but the tumor intake rate is low and the contrast is poor
Solution Approach 1:
The patent employs a composite molecular structure combining FAPI ligand with dimeric scaffold and technetium-99m radiolabeling. This composite approach integrates the tumor-targeting capability of FAPI with the imaging functionality of 99mTc, achieving both high tumor intake rate and improved diagnostic contrast through synergistic effects of the combined structure
Solution Approach 2:
The patent modifies key molecular parameters including introducing dimeric scaffold architecture, optimizing linker lengths and compositions (L1 and L2), and adjusting substituent groups (R1-R8) to enhance the probe's tumor uptake kinetics and retention, thereby improving both intake rate and contrast simultaneously
2Quantity of substance
If FAP-targeting probes are designed to increase tumor intake rate, then the tumor targeting is enhanced, but the complexity of the compound structure increases
Solution Approach 1:
The patent segments the molecular structure into distinct functional modules: the FAPI ligand portion for target recognition, the dimeric scaffold for structural stability and enhanced uptake, the linker regions (L1 and L2) for flexible connection, and the radiolabeling site for imaging. This modular segmentation allows each component to contribute specifically to tumor intake while maintaining overall structural organization
Solution Approach 2:
The dimeric scaffold structure serves multiple functions simultaneously: it provides structural stability, enhances tumor cell uptake through increased molecular weight and reduced renal clearance, maintains solubility through appropriate linker design, and preserves FAP binding affinity. This multi-functionality achieves high tumor intake without proportionally increasing complexity
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 new compound achieves higher tumor intake rates and improved contrast, with reduced uptake in non-target organs, optimizing in-vivo metabolic distribution and pharmacokinetic properties for better clinical application.
Implementation Method 1
Q is a hydrogen atom, or as a nuclide chelating group moiety, is selected from any one group that can undergo chelating coordination with technetium-99mTc
Data Source
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AI summary
A bran-new skeleton 99mTc-FAPI diagnostic probe and use thereof in preparation of drugs or reagents for diagnosing tumors are provided. A fibroblast activation protein-α (FAP)-targeting dimer compound has a structure represented by the following formula. Relative to the traditional FAP inhibitor radioactive drug, a technetium-99m labeled new skeleton FAP inhibitor dimer compound has an extremely high tumor intake rate, and has a relatively high contrast between the tumor and a background and has a good in-vivo biological distribution.