Renal Clearable Peptide Functionalized NaGdF4 Nanodots for High-Efficiency Tracking Orthotopic Colorectal Tumor in Mouse.

The effective delivery of bioimaging probes to a selected cancerous tissue has extensive significance for biological studies and clinical investigations. Herein, the peptide functionalized NaGdF4 nanodots (termed as, pPeptide-NaGdF4 nanodots) have been prepared for highly efficient magnetic resonance imaging (MRI) of tumor by formation of Gd-phosphonate coordinate bonds among hydrophobic NaGdF4 nanodots (4.2 nm in diameter) with mixed phosphorylated peptide ligands including a tumor targeting phosphopeptide and a cell penetrating phosphopeptide. The tumor targeting pPeptide-NaGdF4 nanodots have paramagnetic property with ultrasmall hydrodynamic diameter (HD, c.a., 7.3 nm) which greatly improves their MRI contrast ability of tumor and facilitates renal clearance. In detail, the capability of the pPeptide-NaGdF4 nanodots as high efficient contrast agent for in vivo MRI is evaluated successfully through tracking small drug induced orthotopic colorectal tumor (c.a., 195 mm3 in volume) in mouse.