Typically, nanomedicine was prepared using a nanocarrier to load cargo for specific purposes. In this work, a carrier-free nanosystem for imaging and photodynamic (PDT)/chemo combination therapy was developed using simple self-assembly of a dye and a chemotherapeutic agent. The resulting nanoparticles (I2-IR783/MTX@NPs) exhibited a spherical morphology with a size of 240.6 ± 2.5 nm. I2-IR783/MTX@NPs had substantial internalization in 4T1 murine breast cancer cells and showed a synergistic anticancer effect after NIR light irradiation. Additionally, the 3D tumor model exhibits the same phototoxicity of nanoparticles as a 2D cell culture. The PDT efficiency of the nanosystem in the physiological environment was confirmed by the detection of intracellular reactive oxygen species as well as the live/dead viability/cytotoxicity assay following NIR light exposure. In addition, optical coherence tomography (OCT) was used as an alternative tool to monitor the response after treatment. Therefore, I2-IR783/MTX@NPs show great potential use in theranostic application for breast cancer PDT-chemotherapy.
Keywords: heptamethine cyanine; methotrexate; optical coherence tomography; photodynamic therapy; self-assembly; synergistic treatment.