224Ra (T
1/2 =
3.63 d), an
α-emitting radionuclide, holds significant promise in cancer
endoradiotherapy. Current 224Ra-related therapy is still
scarce because of the lack of reliable radionuclide supply. The 228Th-224Ra radionuclide generator can undoubtedly
introduce continuous and sustainable availability of 224Ra for advanced nuclear medicine. However, conventional metal oxides
for such radionuclide generators manifest suboptimal adsorption capacities
for the parent nuclide, primarily attributable to their limited surface
area. In this work, core–shell SiO2@TiO2 microspheres were proposed to develop as column materials for the
construction of a 228Th-224Ra generator. SiO2@TiO2 microspheres were well prepared and systematically
characterized, which has also been demonstrated to have good adsorption
capacity to 228Th and very weak binding affinity toward 224Ra via simulated chemical separation. Upon introducing 228Th-containing solution onto the SiO2@TiO2 functional column, a 228Th-224Ra generator
with excellent retention of the parent radionuclide and ideal elution
efficiency of daughter radionuclide was obtained. The prepared 228Th-224Ra generator can produce 224Ra with high purity and medical usability in good elution efficiency
(98.72%) even over five cycles. To the best of our knowledge, this
is the first time that the core–shell mesoporous materials
have been applied in a radionuclide generator, which can offer valuable
insights for materials chemistry, radiochemical separation, and biological
medicine.