Peptide functionalized actively targeted MoS nanospheres for fluorescence imaging-guided controllable pH-responsive drug delivery and collaborative chemo/photodynamic therapy.

The combination of imaging and different therapeutic strategies into one single nanoplatform often demonstrates improved efficacy over monotherapy in cancer treatments. Herein, a multifunctional nanoplatform (labelled as MPRD) based on molybdenum disulfide quantum dots (MoS QDs) is developed to achieve enhanced antitumor efficiency by integrating fluorescence imaging, tumor-targeting and synergistic chemo/photodynamic therapy (PDT) into one system. First, polyethylene glycol (PEG)ylated MoS QDs (MP) with desirable stability are synthesized via a hydrothermal process using MoS QDs and carboxyamino-terminated oligomeric PEG as raw materials. Then, MP were conjugated with arginine-glycine-aspartic acid (RGD) peptide via amidation to form a novel nanocarrier (MPR), which possesses strong blue fluorescence, good biocompatibility and αβ receptor-mediated targeting ability. More importantly, MPR generated reactive oxygen species under 808 nm laser activation to realize targeted antitumor PDT. Further doxorubicin (DOX) was loaded onto MPR, which endows MPRD with localized chemotherapy and pH-responsive drug release. The MPRD exhibits improved chemotherapy performance on HepG2 cells (overexpressing integrin αβ) owing to enhanced cellular uptake mediated by αβ receptor and effective drug release triggered by intracellular pH. Notably, MPRD with efficient tumor targeting ability and high chemo/PDT efficacy under NIR laser irradiation is capable of inhibiting HepG2 tumor cell growth both in vitro and in vivo, which is significantly superior to each individual therapy. These findings demonstrate that MPRD holds great potential in effective cancer therapy.