Gadolinium-based macromolecular
contrast agents (CAs) with favorable biocompatibility, targeting specificity, and high relaxivity properties are desired for magnetic resonance imaging (MRI) of
tumors. Herein, a novel triblock polymeric
micelle based on poly(
glycerol) (PG) and poly(ε-
caprolactone) (PCL) was designed as a nanocarrier to fabricate a
tumor targeted
contrast agent (CA). Through conjugating
gadolinium chelates and
folic acid (FA) molecules to the PG block, a triblock-
micelle contrast agent (T-
micelle) formed from self-assembly demonstrated a low critical
micelle concentration (CMC) of 6 mg L-1 and a hydrodynamic diameter of about 250 nm. Compared with small-molecule CAs, the T-
micelle exhibited a higher longitudinal relaxivity (r1) of 14.71 mM-1 s-1. Moreover, the cellular viability assay revealed negligible cytotoxicity, and estimation of targeting capacity showed significant targeting specificity to
tumor cells. In addition, MRI on
tumor-bearing mice confirmed that the T-
micelle could efficiently accumulate at the
tumor region through targeting specificity and provide obvious contrast enhancement. Consequently, the T-
micelle is a promising
gadolinium-based macromolecular CA for
tumor diagnosis.