Magnetic stomatocyte-like nanomotor as photosensitizer carrier for photodynamic therapy based cancer treatment

Amphiphilic block copolymer can self-assemble to stomatocyte-like structure as drug delivery carrier. Photodynamic therapy (PDT) is an emerging modality for cancer treatment. However, PDT has various problems, such as weak tumor accumulation ability of photosensitizers (PSs), short lifetime of singlet oxygen (O-1(2), main reactive oxygen species in PDT) and tumor hypoxia microenvironment, to restrict its therapeutic efficacy. To convey PSs to tumor tissues and improve PDT efficacy, iron oxide nanoparticles (IONPs) were loaded inside the self-assembly stomatocytes-like structure of poly(ethylene glycol) block polystyrene (PEG-b-PS) as nanomotors (IONPs loaded stomatocytes nanomotors, denoted IS-NMs) for PS (zinc phthalocyanine, ZnPc) delivery. The hybrid nanomotors (iron oxide nanoparticles loaded stomatocytes@ZnPc nanomotors, denoted ISP-NMs) can be gathered in tumor tissues under magnetic field owing to magnetism of IONPs. After been trapped by cancer cells, IONPs can catalyze decomposition of endogenous H2O2 to generate O-2 as propelling force for ISP-NMs movement. The motion characteristics of ISP-NMs expanded the distribution of ZnPc to enlarge ROS reactive distribution and enhance the activity of PDT. And the generated O-2 can be supplied for PDT process to ensure its high-performance. Furthermore, ISP-NMs have nuclear magnetic resonance imaging (MRI) function since IONPs are efficient T-2 contrast agent.