Photosensitizer loaded PEG-MoS₂-Au hybrids for CT/NIRF imaging-guided stepwise photothermal and photodynamic therapy

In this study, we developed X-ray computed tomography (CT)/near-infrared fluorescence (NIRF) imaging for visually guiding the photothermal therapy (PTT)/photodynamic therapy (PDT) of antitumor nanocomposites (PEG-MoS₂-Au-Ce6), by adsorbing chlorin e6 (Ce6) to the gold nanoparticle (AuNPs)-decorated molybdenum disulfide (PEG-MoS₂) nanosheets. The NIR photosensitizer Ce6 was adsorbed onto the PEG-MoS₂-Au hybrids viaπ-π stacking and hydrophobic interactions, where Ce6 remained in its quenched state due to the surface plasmon resonance (SPR) capacity of AuNPs, as well as the coupling interaction with PEG-MoS₂ nanosheets. However, Ce6 was dequenched and boosted strong NIR fluorescence signals after being released from the surface of PEG-MoS₂-Au hybrids upon heat generation, thus producing the PDT effect for anti-tumor therapy. Moreover, the PEG-MoS₂ nanosheets and Ce6 in the PEG-MoS₂-Au-Ce6 nanocomposites could be further used for CT and NIRF dual-modal imaging, respectively. In vitro NIR-triggered drug release studies indicated that the PEG-MoS₂-Au-Ce6 nanocomposites rapidly release the drug around the tumor site under the photothermal effect. Therefore, this dual-modality nanosystem simultaneously enables precise cancer diagnosis and therapy.