研究実績の概要 |
In 2017 fiscal year, the following stages of the main plan were accomplished. Composite boron and high-Z element (gold)-containing nanoparticles were synthesized by a new proposed method of cascade ultrasonic dispersion / destruction of micron particles (analyzed by X-ray crystallography) in an aqueous medium. Optical characteristics were analyzed by the light absorption and dynamic light scattering (DLS), showing particle size distribution, zeta-potential and the plasmon resonance. The particles were studied using transmission (TEM) and surface electronic microscopy (SEM). Elemental analysis was performed using inductively-coupled plasma atomic emission spectroscopy (ICP-AES). The efficacy of the accelerator-based neutron source was proven using human and animal tumor and normal cell lines by exponential decrease in colony formation with increase in boron concentration.The method of absorbed dose estimation using combination of boron and gold in tumor cells was tested using human glioma cells with incubated high-Z element nanoparticles and irradiated by epithermal neutrons in an acryl phantom to mimic real treatment conditions.Sample activation resulted in radioactive 198Au isotope generation which was utilized for absorbed dose calculations at each boron concentration.The overall cell-killing effect of the therapy was assessed by a colony-forming assay with evaluation of radiobiological parameters. The results of the study were presented at several conferences and included in scientific publications.
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現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
Implementation of the main plan was slightly delayed due to the limited machine time at the exclusive accelerator-based neutron source and initial procedures of development of absolutely unique nanoparticles, production method and evaluation of the product types prior to application in boron neutron therapy (BNCT) experiments.At the initial stage of the development of a nano-sized composite boron-high-Z-element-compound for BNCT, the funds were also partly spent on transportation to the accelerator-based neutron source as neutron irradiation was required for main stages of the study. Further publishing and manuscript-related costs are planned to be covered in the next fiscal year.
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今後の研究の推進方策 |
The funds will be used according to the main plan of the study, including all preparatory stages of the study flow, with additional costs for publications, transferred to the next fiscal year.Further evaluation of the composite compounds presented as boron and high-Z element-containing nanoparticles in vivo for their toxicity, accumulation in tumor and normal tissues, the tumor/normal tissue accumulation ratio, tumor killing effect (decrease in size or disappearance of the tumor) and the effect on healthy tissues will be performed. Additionally, boron dose estimation in the irradiated tumor tissue and development of tumor localization using the properties of the high-Z element in the composite compounds will be done. Animal (rat and/or mouse) subcutaneous and/or brain tumor models of animal and human brain tumors are planned to be used. Selection of the most appropriate and less toxic compound with better accumulation in tumor tissues and higher tumor to normal tissue ratio, as well as better boron dose estimation properties is planned. Selection of more treatment-sensitive tumors for chosen compounds with further modification of the composite compounds to improve their functionality is planned to advance the research towards future clinical application.
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