A pre-targeting strategy for MR imaging of functional molecules using dendritic Gd-based contrast agents
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Updated: Jun 6, 2026
Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging
Published on: December 4, 2016
Kohei Sano1, Takashi Temma, Takashi Azuma
1Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan.
Purpose:
We aimed to establish a magnetic resonance imaging (MRI) protocol for the sensitive and specific imaging of functional molecules with a pre-targeting strategy utilizing the streptavidin-biotin interaction. Membrane type-1 matrix metalloproteinase (MT1-MMP) was selected as the target molecule.
Procedures:
The biotinylated polyamidoamine dendrimer (PAMAM)-based contrast agent (Bt-PAMAM-DTPA(Gd)) was prepared, and its proton relaxivity (r1) and affinity to streptavidin were evaluated. Tumor-bearing mice were pre-targeted with streptavidin-conjugated anti-MT1-MMP monoclonal antibody (mAb), streptavidin-conjugated negative control IgG, or saline and 3 days later were injected with Bt-PAMAM-DTPA(Gd) followed immediately by MRI for a period of 3 h.
Results:
High r1 (15.5 L mmol(-1) s(-1)) and 1.9-fold higher affinity than D-biotin were obtained. Significantly higher relative tumor signals were observed in mice pre-targeted with streptavidin-conjugated anti-MT1-MMP mAb (165% at 3 h vs. pre-administration) than with saline or streptavidin-conjugated negative control IgG (P < 0.0001).
Conclusions:
This pre-targeting approach can accomplish sensitive and specific in vivo MRI of functional molecules.
