Gadolinium and Platinum in Tandem: Real-time Multi-Modal Monitoring of Drug Delivery by MRI and Fluorescence Imaging

Abstract

A novel dual-imaging cisplatin-carrying molecular cargo capable of performing simultaneous optical and MR imaging is reported herein. This long-lasting MRI contrast agent (r₁ relaxivity of 23.4 mM^-1s^-1 at 3T, 25 ^oC) is a photo-activated cisplatin prodrug (<b>PtGdL</b>) which enables real-time monitoring of anti-cancer efficacy. <b>PtGdL</b> is a model for monitoring the drug delivery and anti-cancer efficacy by MRI with a much longer retention time (24 hours) in several organs such as renal cortex and spleen than GdDOTA and its motif control <b>GdL</b>. Upon complete release of cisplatin, all <b>PtGdL</b> is converted to <b>GdL</b> enabling subsequent MRI analyses of therapy efficacy within its reasonably short clearance time of 4 hours. There is also responsive fluorescence enhancement for monitoring by photon-excitation.