Rare earth activated ZnO nanoparticles as biomarkers

•Efficient energy transfer between ZnO and Eu was observed for NPs codoped with Al.•The 4f–4f luminescence of RE is efficient enough for bio-medical applications.•Two potential routes for the elimination of studied NPs were delineated. Oxide nanoparticles doped with rare-earth ions are tested for applications as nanomarkers in biology and medicine, e.g. for early cancer diagnostics. In this work we describe properties of such markers obtained by a microwave hydrothermal technology. Nanomarkers based on oxide materials (ZnO) are grown and tested for medical and biological applications.