Synthesis and Radioluminescence of PEGylated Eu3+‐doped Nanophosphors as Bioimaging Probes

Abstract

Lanthanide-doped nanophosphors have received significant attention for use in biological sensing and imaging due to their unique optical properties. Much like semiconductor quantum dots (QDs), these luminescent nanocrystals offer several advantages over conventional organic fluorophores, including high photochemical stability, large Stokes shift, and tunable fluorescence emission. [1] Up-conversion nanophosphors, which are capable of absorbing two or more low-energy photons to emit a higher-energy photon, also exhibit favorable characteristics such as long fluorescence lifetimes, no photoblinking, and reduced autofluorescence. [2] The recent development of lanthanide-doped nanophosphors that function in the near-infrared (NIR) spectral range optimal for optical transmission through biological tissues (650–900 nm) has attracted great interest towards in vivo bioim-aging probes. [3–5] Alternatively, high-energy radiation, currently employed in medical imaging modalities, such as X-ray computed tomography (CT) or positron emission tomo graphy (PET), may also be used to excite NIR-emitting radioluminescent nanophosphors (RLNPs) for bioimaging.