Tetraphenylporphyrin‐based dual‐functional medical agent for magnetic resonance and fluorescence imaging

Abstract

A bimodal magnetic resonance imaging contrast agent, TPP‐M‐Gd, was developed by modifying tetraphenylporphyrin (TPP) with a small dendritic molecule as a ligand (M) to chelate gadolinium (Gd) ions. The ligand featured four carboxylate groups, which contributed to good water solubility and a strong combination with metal ions. The longitudinal relaxivity (R1) of the resulting agent was calculated to be 12.45 mM−1 s−1, which is much higher than that of DTPA‐Gd (4.49 mM−1 s−1). The magnetic resonance imaging experiments showed that the newly synthesized contrast agent could enhance T1‐weighted magnetic resonance imaging quality both in vitro and in vivo. In addition, TPP‐M‐Gd exhibited good fluorescent property as shown in cell imaging experiments. The cytotoxicity of TPP‐M‐Gd was even better than that of clinically approved DTPA‐Gd, which makes it a promising dual‐functional medical imaging agent to provide more detailed information about biological and disease‐related events.