Targeted biocompatible nanoplatforms presenting multiple therapeutic functions have great potential for the treatment of cancer. Multifunctional nanocomposites formed by polymeric nanoparticles (PNPs) containing two cytotoxic agents - the drug alisertib and silver nanoparticles - were synthesized. These PNPs have been conjugated with a chlorotoxin, an active targeting 36-amino acid-long peptide that specifically binds to MMP-2, a receptor overexpressed by brain cancer cells. The individual and synergistic activity of these two cytotoxic agents against glioblastoma multiforme was tested both in vitro and in vivo. The induced cytotoxicity in a human glioblastoma-astrocytoma epithelial-like cell line (U87MG) was studied in vitro through a trypan blue exclusion test after 48 and 72 h of exposure. Subsequently, the PNPs' biodistribution in healthy animals and their effect on tumor reduction in tumor-bearing mice were studied using PNPs radiolabeled with (99m)Tc. Tumor reduction was achieved in vivo when using silver/alisertib@PNPs-chlorotoxin.

Dual-modality contrast agents, such as radiolabeled nanoparticles, are promising candidates for a number of diagnostic applications, since they combine the advantages of two different imaging modalities, namely SPECT or PET imaging with MR imaging. The benefit of such a combination is to more accurately interpret disease and abnormalities in vivo, by exploiting the advantages of each imaging technique, i.e. high sensitivity for SPECT/PET, high resolution anatomical information for MRI. In this review article, we provide an overview of recent findings in the synthesis, evaluation and application of radiolabeled iron oxide nanoparticles as dual-modality SPECT/MRI and PET/MRI imaging probes.