Cisplatin-incorporating gelatin-coated gadolinium oxide nanoparticles for cancer theranostics

Recently, much attention has been focused on developing theranostic probes that could make it possible to achieve diagnosis and therapy at the same time. As for theranostics of cancers, cisplatin (<i>cis</i>‒diamminedichloro-platinum(II), CDDP) is a potent anticancer drug; however, cisplatin has some serious drawbacks, including poor water solubility as well as low lipophilicity. Here, we report the synthesis and <i>in vivo</i> evaluation of cisplatin-incorporating gelatin-coated gadolinium oxide (Gd₂O₃) nanoparticles, gelatin-CDDP-Gd₂O₃ NPs, which are a highly efficient theranostic probe for cancer treatment. The controlled release of CDDP from gelatin-CDDP-Gd₂O₃ NPs was realized by the enzymatic degradation of surface-gelatin of NPs with matrix metalloproteinases, MMP-2 and MMP-9, which are highly expressed in cancer cells. Then, gelatin-CDDP-Gd₂O₃ NPs served as a dual contrast agent for magnetic resonance and photoacoustic imaging to give important information on tumor regression under treatment.