Iron Oxide and Various Metal Oxide Hollow Nanoparticles Engineered by One-Pot Double Galvanic Replacement Reaction and the Application for Anti-Cancer Therapy

Although freestanding hollow one-dimensional metal oxide nanoparticles represent an intriguing class of nanomaterials, their practical application has been hampered by complex and expensive synthesis protocols. Here, a new one-pot double Galvanic approach that is both simple and economical is developed for the synthesis of hollow one-dimensional iron oxide nanotubes. In the initial reaction, nanowire substrate (Ag) is oxidized by MnO₄^- ions to form an intermediate nanotube substrate (Mn₃O₄), which is then reduced by Fe²⁺ ions to form an Fe₂O₃ nanotube product. Mn₃O₄ intermediate aid to expand the scope of the reaction for various metal oxides. To test the generality of this approach, the synthesis of SnO₂, CuO, and NiO₂ nanotubes is also examined. Thus, this method could offer robust, economical, and scale-up engineering to generate a variety of metal oxide nanotubes based on the reduction potential hierarchy. As proof-of-principle for the application of these hollow iron-oxide nanoparticles for cancer therapy we have successfully synthesized iron oxide nanoparticle with a characteristic cage shape (IO-NC) using the Galvanic replacement reaction starting from manganese oxide nano cube. We have demonstrated that the cavity of the IO-NC can hold anticancer drugs/RNA molecules and can successfully deliver these drugs to specific sites in vivo. Moreover, when these IO-NC are coated with a lung-tropic exosome, it can effectively target and treat lung metastasis due to breast cancer.