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Rappaport Faculty of Medicine
Graduate Thesis Seminars

Speaker: Shunit Olszakier, B.Eng.
Assistant Professor Lilac Amirav, Faculty of Chemistry
Assistant Professor Itamar Kahn, Faculty of Medicine
Title: Intracellular Labelling of Selected Neurons Utilizing MR-visible Nanoparticle Imaging
Date: Jan 29, 2017
Time: 12:00-13:00
Place: 4th Floor Seminar Room

A central goal of diagnostic medical imaging is to characterize the cellular integrity of brain cells when degenerative processes are on-going but prior to massive cell death that results in gross atrophy. Magnetic resonance imaging (MRI) is a commonly used method in humans and animals able to measure gross integrity. Current intrinsic and contrast agents, however, cannot distinguish between the intra and extra-cellular environments. In my thesis, I developed a novel class of nanoparticles that are dually compatible in both MRI and conventional optical microscopy, allowing the high contrast imaging of the intracellular environment. My research was focused on the establishment of a platform to characterize and optimize these particles for the intracellular environment of neurons and MRI. Ultra-small superparamagnetic Iron Oxide nanoparticles (USPIOs) exhibit strong magnetization that induces microscopic field inhomogeneity in the presence of an external magnetic field. Due to their small size, USPIOs are optimal for internalization into cells with minimal disturbance to biological processes. Testing their effects on cells at the microscopic level required additional labeling of the USPIOs using a fluorescent marker. Quantum dots are considered preferable fluorescent components due to their high temporal stability and resistance to photobleaching compared with dyes. Hence, I combined USPIOs with CdSe@CdS core (a subclass of quantum dots). Our magneto-fluorescent nanoparticles were designed with a unique morphology that prevented undesirable interactions within the hybrid that could abrogate the respective properties. Synthesis of these magneto-fluorescent nanoparticles yielded a strong bi-functional nontoxic contrast agent. In a series of experiments I demonstrate the viability of these nanoparticles for intracellular characterization using MRI and optical microscopy. Our results suggest that imaging of cellular integrity using intracellular contrast agent is feasible.