ROS-Responsive Janus Au/Mesoporous Silica Core/Shell Nanoparticles for Drug Delivery and Long-Term CT Imaging Tracking of MSCs in Pulmonary Fibrosis Treatment.

Mesenchymal stem cell (MSC) therapy has been proven to be a potentially effective approach for idiopathic pulmonary fibrosis (IPF) treatment. However, this strategy is currently limited by the poor curative effect and an insufficient comprehension of the condition of the transplanted MSCs in the remedy of IPF. To address these issues, herein, a nanosystem composed of Janus Au/mesoporous silica core/shell nanoparticles (Janus NPs) is designed for effective therapeutic and real-time tracing of MSCs in MSC-based IPF therapy. The Janus NPs consist of a Au core and a pirfenidone (PFD)-loaded mesoporous silica shell asymmetrically decorated with two targeting moieties: one is reactive oxygen species (ROS)-sensitive thioketal grafted methoxy poly(ethylene glycol) (mPEG-TK), and the other is 1,2-distearoyl--3-phosphoethanolamine (DSPE). The asymmetric decoration on each side of the particle allows long-term anchoring of the Janus NPs on the cell membrane to facilitate the responsive release of PFD in the ROS environment of the fibrotic lung, thereby enhancing the therapeutic efficacy of the transplanted MSCs by improving the microenvironment. Following drug release, the Janus NPs quickly enter into MSCs, achieving long-term computed tomography (CT) imaging tracing of MSCs in IPF model mice for an in-depth comprehension of the cell therapy mechanism. Overall, this work reports on Janus Au/PFD-loaded mesoporous silica core/shell NPs that combine the drug delivery and imaging tracking of MSCs, which may provide a strategy for the stem cell-based treatment of IPF.