Abstract
1093
Objectives: To prepare a kind of embolism bead with the functions of radiosensitization and intra-irradiation for therapy and real-time SPECT/CT monitoring of therapeutic time window, all in one.
Methods: Au nanoparticles (3.8 ± 0.6 nm) were assembled to sub-micron Au particles (186.3 ± 20.4 nm) and then covered with poly-dopamine (PDA) as embolism beads (198.8 ± 23.2 nm) with the ability of radiosensitization. Radioactive iodine-125 was labeled to Au@PDA to introduce the function of intra-irradiation. Finally, the therapeutic effect of Au@PDA-125I were testified in MHCC97H hepatoma cells and the mice models bearing liver tumor. Results: For the therapeutic effects, Au@PDA-125I obviously sensitized the radiation to MHCC97H hepatoma cells and tumor-bearing mice. At the cellular level, after being treated with a relatively low dose (5 Gy) of γ-ray, Au-sensitized radiotherapy (RT) lead to an immediate increase of reactive oxygen species, accompanying with an increase of cell apoptosis. Resulting from the adding of I-125, self-healing of RT-lead double-strand breakage of DNA was suppressed, inducing the continuous increase of cell apoptosis after the RT treatment. Likewise, with three cycles of 5 Gy treatments, the sensitized RT lead to a valid control of tumor volume growth, but had no harm or radioactive residual on/in the radio-sensitive organs, including the thyroid, heart, lung, liver and spleen. Additionally, the photon emission from I-125 makes the beads suitable for SPECT imaging, and the absorption of X-ray makes the beads CT-detectable. Conclusion: As a multi-functional embolism beads, Au@PDA-125I can obviously decrease the required radiation dose of RT, and provide a real-time SPECT/CT monitoring of the therapeutic time window. Figure 1. Biodistribution of intratumorally injected Na125I solution (left) and Au@PDA-125I suspension (right) characterized via planer imaging and CT; and the metabolism curve of injection point (G), thyroid (H) and whole body (I). Figure 2. Change of tumor volume and body weight after being treated with radiotherapy.