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1995 Fiscal Year Final Research Report Summary

Application of photoexcited TiO2 semicondoctor to the treatment of bladder cancer

Research Project

Project/Area Number 05557071
Research Category

Grant-in-Aid for Developmental Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field Urology
Research InstitutionYokohama City University

Principal Investigator

KUBOTA Yoshinobu  Yokohama City Univ., School of Med, Ass.Professor, 医学部, 助教授 (10106312)

Co-Investigator(Kenkyū-buntansha) HASHIMOTO Kazuhito  Univ.Tokyo, School of Engineering, Ass.Professor, 工学部, 助教授 (00172859)
FUJISHIMA Akira  Univ.Tokyo, School of Engineering, Professor, 工学部, 教授 (30078307)
HOSAKA Masahiko  Yokohama City Univ., School of Med, Professor, 医学部, 教授 (30106330)
Project Period (FY) 1993 – 1995
Keywordsphotoexcited semiconductor / TiO2 / Bladder cancer
Research Abstract

A photoexcited titanium dioxide surface has a strong ability to decompose water into hydrogen and oxygen. We have studied this effect in order to use it to kill cancer cells in vitro and in vivo. A distinct cell killing effect was observed on cultured T-24 human bladder cancer cells treated with titanium dioxide particles and 300-400 nm UV light irradiation. Titanium dioxide plus UV light also dramatically suppressed the tumour growth of T-24 cells that were implanted in nude mice. Cells cultured on the titanium dioxide electrode were also killed under UV irradiation when the electrode was anodically polarised, suggesting that photogenerated holes are involved in the cell killing. The cell killing effect caused by titanium dioxide particles plus UV light irradiation was significantly hampered in the presence of L-cysteine and catalase, scavengers of hydroxyl radicals and hydrogen peroxide respectively. Transmission electron microscopic observations showed the titanium dioxide particles to be distributed on the cell surface and inside the cells. These results suggest that titanium dioxide particles under UV light irradiation produced photogenerated holes on the surface yielding hydroxyl radicals and hydrogen peroxide inside or outside the cells and the cells were then killed by the action of these highly oxidising molecules. The possible application of photoexcited titanium dioxide particles to cancer treatment as a new anti-cancer modality is discussed.

  • Research Products

    (11 results)

All Other

All Publications (11 results)

  • [Publications] Cai,R.et al: "Photoelectrochemistry of TiO_2 particles : efficient electron transfer from the TiO_2 particles to a redox enzyme" J.Electroanal.Chem.360. 237-245 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Kubota,Y.et al: "Photokilling of T-24 human bladder cancer cells with titanium oxide." British Journal of Cancer. 70. 1107-1111 (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Sakai,H.et al: "Intra cellular Ca^<2+> concentration change of T-24 cell under irradiation in the presence of TiO_2 ultrafine particle" Biochimica et Biophysia Acta. 1201. 259-265 (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Sakai,H.et al: "Selective Killing of a single cancerous T-24 cell with TiO_2 semiconducting microelectrode under irradiation" Chemistry letters. 1995. 185-186 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 窪田吉信他: "光励起半導体を用いる癌の新しい光化学療法" 病態生理. 12. 878-883 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 藤嶋昭他: "がん治療やMRSA殺菌に応用できる光触媒反応" 表面科学. 16. 24-29 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 藤嶋昭: "1億人の化学-15-光が活躍する" 日本化学会・大日本図書, 229 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Cai, R., Baba, R., Hashimoto, K., Kubota, Y., Fujishima, A.: "Photoelectrochemistry of TiO2 particles : efficient electron transfer from the TiO2 particles to a redox enzyme" J.Electroanal.Chem.360. 237-245 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Kubota, Y., Syuin, T., Kawasaki, C., Hosaka, M., Kitamura, H., Cai, R., Sakai, H., Hashimoto, K., Fujishima, A.: "Photokilling of T-24 humann bladder cancer cells with titanium dioxide" Br.J.Cancer. 70. 1107-1111 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Sakai, H., Ito, E., Cai, R., Yoshioka, T., Kubota, Y., Hashimoto, K., Fujishima, A.: "Intracellular Ca^<2+> concentration change of T-24 cell under irradiation in the presence of TiO_2 ultrafine particle" Biochimica et Biophysica Acta. 259-265 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Sakai, H., Baba, R., Hashimoto, K., Kubota, Y., Fujishima, A.: "Serective killing of a single cancerous T-24 cell with TiO_2 semiconducting microelectorode under irradiation" Chemistry Letters. 1995. 185-186 (1995)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-03-09  

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