Multifunctional Nanosystem for Synergistic Tumor Therapy Delivered by Two-Dimensional MoS₂

A multifunctional nanosystem based on two-dimensional molybdenum disulfide (MoS 2 ) was developed for synergistic tumor therapy. MoS 2 was stabilized with lipoic acid (LA)-modified poly(ethylene glycol) and modified with a pH-responsive charge-convertible peptide (LA-K 11 (DMA)). Then, a positively charged photosensitizer, toluidine blue O (TBO), was loaded on MoS 2 via physical absorption. The negatively charged LA-K 11 (DMA) peptide was converted into a positively charged one under acidic conditions. Charge conversion of the peptide could reduce the binding force between positively charged TBO and MoS 2, leading to TBO release. Furthermore, the positively charged nanosystem was easily endocytosed by cells. Photo-induced hyperthermia of MoS 2 in the tumor areas could promote TBO release and exhibited photothermal therapy. In vitro and in vivo results demonstrated that fluorescence and photo-induced reactive oxygen species (ROS) generation of TBO were severely decreased by MoS 2 under normal conditions. While in the acidic condition, the pH-responsive nanosystem exhibited a highly specific and efficient antitumor effect with TBO release and photo-induced ROS generation, suggesting to be a promising accessory for synergistic tumor therapy.