Magnetic Resonance Imaging is a powerful diagnostic technique, widely applied in the clinic and in pre-clinical research. Magnetic contrast agents are routinely used to enhance image contrast, and help discriminate between different tissues, or between pathological and healthy states. Objective of this project is the development of novel probes for Magnetic Resonance Imaging applications. Specifically, we aim to:
- develop MR imaging nanosensors capable of reporting quantitatively on the cellular and tissutal microenvironment;
- increase molecular specificity and sensitivity of MR contrast agents;
- design nanoprobes that exploit specific physiological transport mechanisms to target cellular and tissue compartments otherwise inaccessible to conventional contrast agents;
- develop MR imaging methods and image analysis approaches to exploit the full potential of novel imaging probes.
Specific projects we are currently pursuing include:
Development of ratiometric magnetic nanosensors
Recent studies have shown that T2 MR relaxivity of magnetic nanoparticles depends of their aggregation state, and increases when particles are assembled forming larger aggregates. This phenomenon can be exploited to develop magnetic nano-probes that are sensitive to the presence of molecular targets that promote cross-linking between particles, or to enzymatic activity that breaks up multi-particle assemblies. The goal of this research is to design a ratiometric magnetic nanosensors that exploits aggregation-induced T2 contrast enhancement together with the parallel measurements of a parameter independent (or less dependent) on the aggregation state, such as T1 Relaxation Rates.
High-relaxivity magnetic nanoparticles for Cerebral Blood Volume (CBV) measurements
Functional MRI, i.e. MRI as applied to map brain function, relies on the Blood Oxygenation Level Dependent (BOLD) phenomenon. Alternative methods, like fMRI based on Cerebral Blood Volume measurements, may provide increased contrast-to-noise ratio, and to the possibility to reduce susceptibility-artifacts through the use of spin-echo methods. However, CBV MRI requires the use of blood pool contrast agents to sensitize the images to haemodynamic changes. We are developing a new class of iron oxide nanoparticles with large saturation magnetization and able to obtain stronger CBV-weighting, whilst reducing the systemic nanoparticles load and potential safety risks.