Liver-targeting MRI contrast agent based on galactose functionalized o-carboxymethyl chitosan

Abstract

Commercial gadolinium (Gd)-based contrast agents (GBCAs) play important role in clinical diagnostic of hepatocellular carcinoma, but their diagnostic efficacy remained improved. As small molecules, the imaging contrast and window of GBCAs is limited by low liver targeting and retention. Herein, we developed a liver-targeting gadolinium (Ⅲ) chelated macromolecular MRI contrast agent based on galactose functionalized o-carboxymethyl chitosan, namely, CS-Ga-(Gd-DTPA)n, to improve hepatocyte uptake and liver retention. Compared to Gd-DTPA and non-specific macromolecular agent CS-(Gd-DTPA)n, CS-Ga-(Gd-DTPA)n showed higher hepatocyte uptake, excellent cell and blood biocompatibility in vitro. Furthermore, CS-Ga-(Gd-DTPA)n also exhibited higher relaxivity in vitro, prolonged retention and better T1-weighted signal enhancement in liver. At 10 days post-injection of CS-Ga-(Gd-DTPA)n at a dose of 0.03 mM Gd/Kg, Gd had a little accumulation in liver with no liver function damage. The good performance of CS-Ga-(Gd-DTPA)n gives great confidence in developing liver-specifc MRI contrast agents for clinical translation.

Precise diagnosis of cardiac‐cerebral vascular diseases with magnetic resonance imaging‐based nanoprobes

“…Gd-chelate derivatives, such as Gd-DTPA, can shorten the longitudinal relaxation time of protons and brighten the blood-pool, and have therefore been dominantly applied in the clinical MRI diagnosis of vasculopathy [22]. However, the small molecular Gd chelates can extravasate from blood vessels and diffuse into the intercellular space very quickly, not only resulting in short circulation times, but also hindering the attainment of accurate angiograms [23][24][25][26]. Additionally, T 1 -weighted MRA is not suitable for depicting the anatomical structure of the vasculature in encephalocele, especially the cerebral microvasculature.…”