Rare earths based nir luminomagnetic nanoparticles and their multimodal applications in biomedical imaging
Medical imaging is one of the most important techniques in the medical field for diagnostics and analysis of biological tissues. The most common imaging modalities are X-ray, Magnetic Resonance Imaging (MRI), and optical imaging. In each of these imaging techniques, several contrast agents are used to improve the image resolution. There are several contrast agents available that are specific for a particular application and only include one functionality. In addition, most of the contrast agents available today have several limitations such as low image resolution, low thermal stability, toxicity, cost of production etc. The development of an ideal contrast agent with multiple functionalities that overcome most of these limitations is a challenging topic in the medical industry. Furthermore, by adding multiple functionalities into a single contrast agent the benefits would provide a decrease in cost and time by imaging multiple modalities simultaneously. Though there are various attempts in this area by several researchers around the world, the idea of developing a core-shell free multifunctional contrast agent with near infrared (NIR) imaging features and magnetic properties is novel. This doctoral dissertation is focused on the investigation of rare earth doped, NIR active, luminomagnetic nanocrystals (NCs) that have the potential to be effective contrast with multiple modalities. The main content of the thesis is about the development, characterization, and implementation of Nd 3+ doped YF3, GdF3, and Na(Lu0.5Gd 0.5)F4. The "as prepared" and surface functionalized NCs are characterized for their phase, morphology, and detailed optical characteristics such as absorption, emission and quantum yield. Magnetic properties are studied by magnetization experiments. In order to show the proof of concept as a multifunctional imaging agent various imaging experiments such as confocal intracellular imaging, NIR optical imaging, X-ray imaging and magnetic resonance imaging experiments were conducted and their performance was validated by the outcome of these experiments.