The purpose of this study was to develop a multifunctional theranostic probe for imaging (magnetic resonance imaging [MRI] and single-photon emission computed tomography [SPECT]) and therapy (photodynamic therapy). For this purpose, Tc-99m-labeled lupulone-conjugated Fe3O4@TiO2 nanocomposites (99mTc-DTPA-Fe3O4@TiO2-HLP and 99mTc-DTPA-Fe3O4@TiO2-ALP nanocomposites) were synthesized. The average diameter of the nanocomposites was 171 ± 20 nm as seen on transmission electron microscopy images. Fe3O4@TiO2 nanocomposites exhibited fluorescence spectra at an emission wavelength of 314 nm. Lupulone-conjugated Fe3O4@TiO2 nanocomposites were spherical-shaped with a suitable dispersion and without visible aggregation, and their radiolabeling yields were over 85%. Healthy (RWPE-1 normal human prostate epithelial cell line) and cancer prostate cell lines (PC-3 human prostate cancer cell line) were used to determine the in vitro biological behavior of the nanocomposites. The PC-3 cells treated with lupulone-conjugated Fe3O4@TiO2 nanocomposites showed a lower cell viability compared with RWPE-1 cells treated with lupulone-conjugated Fe3O4@TiO2 nanocomposites. Lupulone-modified Fe3O4@TiO2 nanocomposites may serve in the future as a multifunctional probe for positron emission tomography (PET)/MRI, photodynamic therapy, and hyperthermia therapy of cancer.
Keywords: Fe3O4@TiO2; Tc-99m; lupulone; nanocomposites; prostate cancer cells.