이 연구는 γ선 및 x선 조사 시 AuNPs 입자의 방사선감수성의 향상을 생물물리학적으로 평가하기 위해 두 가지 실험을 시행하였다. 생물학적 방사선 감수성의 평가에 앞서 6시간, 12시간, 18시간, 24시간 incubation한 후 세포생존율(surviving Fraction, SF)값을 비교하여 AuNPs 입자의 독성 여부와 세포질에 입자의 균일 된 분포 여부를 확인 해 보았다. incubation time에 따라 세포생존율(surviving Fraction, SF)이 낮아지지 않음을 확인한 다음 γ선 및 x선 조사 후 Clonogenic assay 실시하고 세포생존율(surviving Fraction, SF)을 구하여 방사선 감수성을 비교 평가하였다. 방사선량 증가 시 세포생존율(surviving Fraction, SF)이 계속해서 낮아졌고 8Gy 조사 시 최대치로 약 30%의 차이가 있음을 확인하였다. 또한 Gate v6.1을 사용하여 몬테카를로 시뮬레이션 후 percent depth dose(PDD)를 구한 뒤 선량 평가하여 약 40% Dose Enhancement가 있음을 확인하였다. 두 가지 실험에 따라 생물물리학적으로 AuNPs 입자는 방사선 감수성이 향상되도록 하며 이는 nanoparticle을 이용한 방사선 병합 치료 시 치료 성적 향상에 큰 도움이 될 것으로 보인다.

The purpose of this study is to investigate whether gold nanoparticles had radiosensitization when combined with gamma and x ray beam. Cytotoxicity was mearsured with comparing survival fraction after incubated time 6,12,18 and 24 hours. Clonogenic assay was employed to assess survival fraction of cells with and without gold nanoparticles treatment following gamma ray irradiation. The most of gold nanoparticles were distributed in the cytoplasm. And the toxicity of gold nanoparticles used this study were found to be non-cytotoxic. And we also observed enhancement by about 40% in RBE value for gamma ray irradiation of cells treated with gold nanoparticles. Dose reduction of about half for gamma ray irradiation is demonstrated for gold nanoparticles treated cells as compared to untreated cells. In cells with exposed to gamma ray, DNA damage was increased when compared to only radiation exposed cells. The study revealed a significant reduction in radiation dose for killing the cells with internalized gold nanoparticles as compared to the cells without gold nanoparticles. The gold nanoparticles treatment resulted in enhancement of radiation effect as evident from increase in relative biological effectiveness values for photon irradiated cells.

ABSTRACT
 Ⅰ. INTRODUCTION
 Ⅱ. MATERIAL AND METHODS
  1. 독성검사 및 세포생존율 측정
  2. percent depth dose(PDD) 측정
 Ⅲ. RESULT
 Ⅳ. DISCUSSION AND CONCLUSION
 Reference
 요 약

• Eunae Choi(Department of Bio-convergence Engineering, Korea university) | 최은애 Corresponding Author
• Jaeman Son(Department of Bio-convergence Engineering, Korea university) | 손재만