Synthesis and characterization of amphiphilic lanthanide chelates as potential contrast agents for bimodal MRI and optical imaging

The powerful in vivo technique of magnetic resonance imaging (MRI) is ubiquitous in clinical diagnostics and optical imaging is becoming an emerging technique of interest. Each imaging technique has its own strengths and weaknesses, the combination of different, complementary techniques can overcome inherent limitations that are associated with one individual technique. Whereas MRI is ideal for whole body images due to its good spatial resolution, its sensitivity is rather low so that large concentrations of Gd(III)-based contrast agents are required. Luminescence-based imaging, on the other hand, can provide high-resolution images, but this technique is only suitable for thin tissue samples because of the low optical transparency of biological tissue. Ever since the introduction of MRI as a diagnostic tool, the interest in developing more efficient contrast agents (CAs) has grown tremendously. In a recent effort to enhance the imaging performance of CAs, probes combining MRI and luminescent properties have been created in order to combine a good resolution with high sensitivity thus allowing investigation of samples in exquisite detail. In this project we aim to employ Dy(III) and also explore the efficacy of the Tb(III) ion as negative T2 CAs. Similarly to Dy(III), Tb(III) is also characterized by strong luminescence and possesses a large magnetic moment, so that the CA remains efficient at high magnetic field.