FAPI Dimer PET Imaging Agent for Tumor Residence Time
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Solution Overview
Problem
Current PET imaging agents for tumors, such as 68Ga-FAPI-46, have a short residence time in tumors with low FAP expression, leading to unsatisfactory uptake and imaging effects.
Innovation Solution
Development of a FAPI dimer compound with an amphiphilic polyethylene glycol (PEG) chain and a dimerized structure, labeled with 68Ga, to create a PET imaging agent that improves in vivo kinetic properties and residence time in tumors, enhancing uptake and imaging effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If 68Ga-FAPI-46 is used for PET imaging, then the imaging agent can quickly enter the tumor, but the residence time is relatively short resulting in unsatisfactory uptake and imaging effects in tumors with low FAP expression
Solution Approach 1:
The FAPI molecule is divided into two identical units linked together to form a dimer structure. This segmentation approach creates a bivalent imaging agent that can simultaneously engage with two FAP receptors, thereby increasing residence time and uptake in tumors with low FAP expression while preserving the rapid entry capability of the original monomer
Solution Approach 2:
Two FAPI units are merged into a single dimer molecule through a linker containing amphiphilic polyethylene glycol chains. This merging creates a multifunctional imaging agent that combines the tumor-penetrating capability of individual FAPI units with enhanced binding avidity through simultaneous engagement of multiple receptors
2Duration of action of moving object
If FAPI dimer compound with amphiphilic PEG chain is developed, then the residence time and uptake in tumors are improved, but the molecular structure becomes more complex
Solution Approach 1:
The amphiphilic PEG chain linker introduces specific physicochemical parameters including hydrophilic-hydrophobic balance, flexible chain length, and controlled spacing between FAPI units. These parameter optimizations enhance solubility, stability, and binding characteristics without excessive structural complexity
Solution Approach 2:
The FAPI dimer compound represents a composite molecular structure combining two FAPI units with a PEG-based linker. This composite design integrates the targeting capability of FAPI with the stabilizing and solubilizing properties of amphiphilic PEG chains, achieving enhanced performance through controlled molecular composition
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 FAPI dimer-based PET imaging agent demonstrates improved stability and specificity to FAP, achieving higher uptake and target-to-background ratios even in tumors with low FAP expression, providing better diagnostic accuracy.
Implementation Method 1
fibroblast activation protein inhibitor (FAPI) dimer compound... FAP-targeted 68Ga-FAPI-46 PET/CT imaging... FAP has become an attractive target for studying tumor stromal cell biology
Implementation Method 2
an amphiphilic polyethylene glycol (PEG) chain and a dimerized structure... can improve the in vivo kinetic properties of the compound and prolong a residence time
Implementation Method 3
FAPI dimer-based positron emission tomography (PET) imaging agent... has a long residence time in a tumor and a prominent imaging effect
Implementation Method 4
68Ga-FAPI-46 PET/CT imaging... 68Ga, to create a PET imaging agent
Data Source
AI summary
Provided are a fibroblast activation protein inhibitor (FAPI) dimer compound, an FAPI dimer-based positron emission tomography (PET) imaging agent for tumor diagnosis, and a preparation method and use thereof. An amphiphilic polyethylene glycol (PEG) chain and a dimerized structure of FAPI in the FAPI dimer compound with a structure shown in formula I can improve the in vivo kinetic properties of the compound and prolong a residence time of the compound in a tumor, thereby improving the uptake and imaging effects in the tumor. The accurate tumor diagnosis can be achieved by labeling the FAPI dimer compound with a diagnostic nuclide (68Ga), which has promising application prospects in PET imaging for diagnosis and in the preparation of a therapeutic nuclide (such as 177Lu or 90Y)-labeled drug for treating a FAP-α-expressing tumor.