Tumor-microenvironment-induced degradation of ultrathin gadolinium oxide nanoscrolls for magnetic-resonance-imaging-monitored, activatable cancer chemotherapy

The development of biodegradable inorganic nanoparticles with a tumor microenvironment‐activated therapeutic mode of action is urgently needed for precision cancer medicine. Herein, the synthesis of ultrathin lanthanide nanoscrolls (Gd${}_2$O${}_3$ NSs) is reported, which biodegrade upon encountering the tumor microenvironment. The Gd${}_2$O${}_3$ NSs showed highly controlled magnetic properties, which enabled their high‐resolution magnetic resonance imaging (MRI). Importantly, Gd${}_2$O${}_3$ NSs degrade in a pH‐responsive manner and selectively penetrate tumor tissue, enabling the targeted release of anti‐cancer drugs. Gd${}_2$O${}_3$ NSs can be efficiently loaded with an anti‐cancer drug (DOX, 80 %) and significantly inhibit tumor growth with negligible cellular and tissue toxicity both in vitro and in vivo. This study may provide a novel strategy to design tumor microenvironment‐responsive inorganic nanomaterials for biocompatible bioimaging and biodegradation‐enhanced cancer therapy. (© 2019 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)