Preparation of Bimodal Nanoprobes for Fluorescent and Magnetic Resonance Imaging by Conjugating Gadolinium Complexes to Quantum Dots.

The development of strategies to optimize the conjugation of Gd3+ complexed to quantum dots (QDs) has been increasingly explored. The aim is to combine two imaging techniques, improving diagnostics and overcoming the limitations of individual methods. This chapter describes the preparation of bimodal systems by conjugating GdDOTA-thiolated complexes with fluorescent QDs through dative bonds, in an aqueous medium. Due to the toxicity of the Gd3+ ion, structural modifications of the DOTA-based ligands were evaluated to ensure that these changes did not compromise the complexation efficiency or the stability of the resulting complexes. The optical and relaxometric properties of the conjugated complexes to the QDs were also assessed.