Organic Fluorophore Coated Polycrystalline Ceramic LSO:Ce Scintillators for X-ray Bioimaging.

ABSTRACT

The current effort demonstrates that lutetium oxyorthosilicate doped with 1-10% cerium (Lu2SiO5Ce, LSOCe) radioluminescent particles can be coated with a single dye or multiple dyes and generate an effective energy transfer between the core and dye(s) when excited via X-rays. LSOCe particles were surface modified with an alkyne modified naphthalimide (6-piperidin-1-yl-2-prop-2-yn-1-yl-1 H-benzo[ de]isoquinoline-1,3-(2 H)-dione, AlNap) and alkyne modified rhodamine B ( N-(6-diethylamino)-9-{2-[(prop-2-yn-1-yloxy)carbonyl]phenyl}-3 H-xanthen-3-ylidene)- N-ethylethanaminium, AlRhod) derivatives to tune the X-ray excited optical luminescence from blue to green to red using Förster Resonance Energy Transfer (FRET). As X-rays penetrate tissue much more effectively than UV/visible light, the fluorophore modified phosphors may have applications as bioimaging agents. To that end, the phosphors were incubated with rat cortical neurons and imaged after 24 h. The LSOCe surface modified with AlNap was able to be successfully imaged in vitro with a low-output X-ray tube. To use the LSOCe fluorophore modified particles as imaging agents, they must not induce cytotoxicity. Neither LSOCe nor LSOCe modified with AlNap showed any cytotoxicity toward normal human dermal fibroblast cells or mouse cortical neurons, respectively.