ROS-activatable nanocomposites for CT imaging tracking and antioxidative protection of mesenchymal stem cells in idiopathic pulmonary fibrosis therapy.

Mesenchymal stem cell (MSC) transplantation is emerging as a promising approach in the treatment of idiopathic pulmonary fibrosis (IPF), while it is still impeded by several challenges, including unsatisfactory treatment outcomes due to the poor survival of transplanted MSCs, and the lack of non-invasive and long-term imaging modality for tracking the behavior of MSCs. Herein, copper-based nanozyme (CuxO NPs) and gold nanoparticles (Au NPs) were encapsulated in oxidation-sensitive dextran (Oxi-Dex), a dextran derivative with reactive oxygen species (ROS)-responsiveness, forming a kind of novel nanocomposites (assigned as RSNPs) to act as ROS scavengers and computer tomography (CT) imaging tracers. After being internalized by MSCs, RSNPs enabled continuous CT imaging tracking of the transplanted MSCs for 21 days in IPF treatment, obtaining the location and distribution of the transplanted MSCs. Once MSCs were attacked by oxidative stress, the intracellular RSNPs could activate ROS clearance on demand by releasing CuxO NPs, thereby enhancing the therapeutic efficacy against IPF by improving cell survival. Taken together, a novel multifunctional RSNP was fabricated to label MSCs for CT imaging tracking and clearing superfluous ROS, presenting a promising high-efficient IPF therapy.