Rodlike MSN@Au Nanohybrid-Modified Supermolecular Photosensitizer for NIRF/MSOT/CT/MR Quadmodal Imaging-Guided Photothermal/Photodynamic Cancer Therapy

Recently, rodlike nanomaterials with specific aspect ratio for efficient cellular uptake have received enormous attention. For functional nanomaterials, such as photothermal agents, large surface areas for their rod-shaped exterior that increase the amount of light absorbed would lead to a higher absorption coefficient as well as drug-loading property. In this project, we coated rodlike mesoporous silica with gold nanoshells (MSNR@Au hybrid), modifying them with ultrasmall gadolinium (Gd)-chelated supramolecular photosensitizers, TPPS4 (MSNR@Au-TPPS4(Gd)), which could be applied to near-infrared fluorescence/multispectral optoacoustic tomography/computed tomography/magnetic resonance imaging and imaging-guided remotely controlled photothermal (PTT)/photodynamic (PDT) combined antitumor therapy. Gold nanoshells, as a perfect PTT agent, were used to assemble the rodlike mesoporous silica nanoparticles with larger superficial area and higher drug loading, thus obtaining the MSNR@Au hybrid. HS-β-CD, which was used as the host, was adsorbed on the gold nanoshell (MSNR@Au-β-CD) to link TPPS4(Gd) through the host–guest reaction, thus forming CD-TPPS4 supramolecular photosensitizers (supraPSs). Compared with conventional PSs, supraPSs have host screens, which could reduce the self-aggregation of TPPS4, and consequently generate 1O2 with high efficiency. The in vivo quadmodal imaging of MSNR@Au-TPPS4(Gd) nanoparticles revealed an intensive tumor uptake effect after injection. The in vivo antitumor efficacy further testified that the synergistic therapy, which was more efficient than any other monotherapy, exhibited an excellent tumor inhibition therapeutic effect. As a result, this encourages to further explore multifunctional theranostic nanoparticles based on gold shells for combined cancer therapy.