Synthesis, Radiolabelling and In Vitro Imaging of Multifunctional Nanoceramics

Molecular imaging has become a powerful technique in preclinical and clinical research aiming towards the diagnosis of many diseases. In this work, we address the synthetic challenges in achieving lab‐scale, batch‐to‐batch reproducible copper‐64‐ and gallium‐68‐radiolabelled metal nanoparticles (MNPs) for cellular imaging purposes. Composite NPs incorporating magnetic iron oxide cores with luminescent quantum dots were simultaneously encapsulated within a thin silica shell, yielding water‐dispersible, biocompatible and luminescent NPs. Scalable surface modification protocols to attach the radioisotopes 64Cu (t1/2=12.7 h) and 68Ga (t1/2=68 min) in high yields are reported, and are compatible with the time frame of radiolabelling. Confocal and fluorescence lifetime imaging studies confirm the uptake of the encapsulated imaging agents and their cytoplasmic localisation in prostate cancer (PC‐3) cells. Cellular viability assays show that the biocompatibility of the system is improved when the fluorophores are encapsulated within a silica shell. The functional and biocompatible SiO2 matrix represents an ideal platform for the incorporation of 64Cu and 68Ga radioisotopes with high radiolabelling incorporation. Radioactive nanoceramic: Scalable and post‐synthetic surface modification protocols to attach 64Cu and 68Ga radioisotopes to fluorogenic composite materials are reported. Covalent and non‐covalent synthetic procedures are designed to obtain versatile, adaptable magnetic and luminescent biocompatible core‐shell nanoceramics which were extensivelly characterised, e. g. by DLS, TEM, EDX. The potential of such radio‐nanocomposites to act as cellular bioimaging agents are investigated via confocal fluorescence microscopy, UV‐Vis, single and multi‐photon FLIM and their cellular viability probed by by MTT assays.