Journal of Medical Ultrasonics

, Volume 42, Issue 4, pp 449–455 | Cite as

Enhanced mechanical damage to in vitro cancer cells by high-intensity-focused ultrasound in the presence of microbubbles and titanium dioxide

  • Katsuro Tachibana
  • Hitomi Endo
  • Loreto B. Feril
  • Seyedeh Moosavi Nejad
  • Hiromasa Takahashi
  • Kyoichi Narihira
  • Toshihiro Kikuta
Original Article



To evaluate in vitro the feasibility of therapeutic high-intensity-focused ultrasound (HIFU) combined with microbubbles and titanium dioxide (TiO2).


Oral squamous cell carcinoma cells (HSC-2) were sonicated using a HIFU transducer with a resonant frequency of 3.5 MHz, 30 mm in diameter, and focal length of 50 mm. The ultrasound intensity was 210 W/cm2, and two pulses (0.5 s each) were sonicated for each cell sample (9 × 104 cells per well). Immediately after HIFU, the viable cells were measured by an automated cell counter. The survival rate was measured in the presence of microbubbles (Sonazoid) and peroxo titania-silica (R-P-TS) or anatase titania-silica (R-A-TS) TiO2.


Cell viability immediately following sonication in the presence of TiO2 (R-A-TS) and TiO2 (R-P-TS) was 65.5 ± 0.7 and 59.4 ± 3.3 %, respectively. A marked decrease in cell viability was seen when microbubbles were added to the above cell conditions. Specifically, cell viability decreased to 14.0 ± 0.1 and 4.4 ± 0.9 % when microbubbles were added to samples containing TiO2 (R-A-TS) and TiO2 (R-P-TS), respectively.


Immediate in vitro cell killing was observed with short pulsed duration HIFU sonication with a combination of microbubbles and TiO2. This finding suggests that TiO2 could have caused enhanced mechanical cell destruction by microbubbles.


High-intensity-focused ultrasound (HIFU) Titanium dioxide Microbubbles Cell damage 



This study was supported in part by the Japanese Society of Ultrasound in Medicine 2013 Research Grant.

Conflict of interest

Katsuro Tachibana, Hitomi Endo, Loreto Feril, Seyedeh Moosavi Nejad, Hiromasa Takahashi, Kyoichi Narihira, and Toshihiro Kikuta all declare that they have no conflict of interest.

Ethical standard

This article does not contain any experiments with human or animal subjects performed by any of the authors.


  1. 1.
    Ogino C, Shibata N, Sasaki R, et al. Construction of protein-modified TiO2 nanoparticles for use with ultrasound irradiation in a novel cell injuring method. Bioorg Med Chem Lett. 2010;20:5320–5.CrossRefPubMedGoogle Scholar
  2. 2.
    Harada Y, Ogawa K, Irei Y, et al. Ultrasound activation of TiO2 in melanoma tumors. J Control Release. 2011;149:190–5.CrossRefPubMedGoogle Scholar
  3. 3.
    Tachibana K, Tachibana S. Albumin microbubble echo-contrast material as an enhancer for ultrasound accelerated thrombolysis. Circulation. 1995;92:1148–50.CrossRefPubMedGoogle Scholar
  4. 4.
    Ohl CD, Arora M, Ikink R, et al. Sonoporation from jetting cavitation bubbles. Biophys J. 2006;91:4285–95.PubMedCentralCrossRefPubMedGoogle Scholar
  5. 5.
    Abe N, Nakamoto H, Suzuki T, et al. Ex vivo evaluation of high-intensity focused ultrasound with ultrasonic-induced cavitation bubbles. J Med Ultrasonics. 2014;41:3–9.CrossRefGoogle Scholar
  6. 6.
    Wu J. Shear stress in cells generated by ultrasound. Prog Biophys Mol Biol. 2007;93:363–73.CrossRefPubMedGoogle Scholar
  7. 7.
    Nejad SM, Hosseini SHR, Akiyama H, et al. Optical observation of cell sonoporation with low intensity ultrasound. Biochem Biophys Res Commun. 2011;413:218–23.CrossRefGoogle Scholar
  8. 8.
    Esquivel K, Arriaga L, Rodríguez F, et al. Development of a TiO2 modified optical fiber electrode and its incorporation into a photoelectrochemical reactor for wastewater treatment. Water Res. 2009;43:3593–603.CrossRefPubMedGoogle Scholar
  9. 9.
    Tsuang YH, Wu J, Zhang Z, et al. Studies of photokilling of bacteria using titanium dioxide nanoparticles. Artif Organs. 2008;32:167–74.CrossRefPubMedGoogle Scholar
  10. 10.
    Cheng CL, Sun D, Chu W, et al. The effects of the bacterial interaction with visible-light responsive titania photocatalyst on the bactericidal performance. J Biomed Sci. 2009;16:7.PubMedCentralCrossRefPubMedGoogle Scholar
  11. 11.
    Zubkov T, Stahl D, Thompson TL, et al. Ultraviolet light-induced hydrophilicity effect on TiO2(110)(1 × 1). Dominant role of the photooxidation of adsorbed hydrocarbons causing wetting by water droplets. J Phys Chem B. 2005;109:15454–62.CrossRefPubMedGoogle Scholar
  12. 12.
    Wang J, Go Y, Liu B, et al. Detection and analysis of reactive oxygen species (ROS) generated by nano-sized TiO2 powder under ultrasonic irradiation and application in sonocatalytic degradation of organic dyes. Ultrason Sonochem. 2011;18:177–83.CrossRefPubMedGoogle Scholar
  13. 13.
    Shimizu N, Ogino C, Derider MF, et al. Sonocatalytic facilitation of hydroxyl radical generation in the presence of TiO2. Ultrason Sonochem. 2008;15:988–94.CrossRefPubMedGoogle Scholar
  14. 14.
    Chihara Y, Fujimoto K, Konod M, et al. Anti-tumor effects of liposome-encapsulated titanium dioxide in nude mice. Pathobiology. 2007;740:353–8.CrossRefGoogle Scholar
  15. 15.
    Zhu YL, Eaton JW, Li C. Titanium Dioxide (TiO2) nanoparticles preferentially induce cell death in transformed cells in a Bak/Bax-independent fashion. PLoS One. 2012;7:e50607.PubMedCentralCrossRefPubMedGoogle Scholar

Copyright information

© The Japan Society of Ultrasonics in Medicine 2015

Authors and Affiliations

  • Katsuro Tachibana
    • 1
  • Hitomi Endo
    • 1
  • Loreto B. Feril
    • 1
  • Seyedeh Moosavi Nejad
    • 1
  • Hiromasa Takahashi
    • 2
    • 3
  • Kyoichi Narihira
    • 2
  • Toshihiro Kikuta
    • 2
  1. 1.Department of AnatomyFukuoka University School of MedicineFukuokaJapan
  2. 2.Department of Oral SurgeryFukuoka University School of MedicineFukuokaJapan
  3. 3.Department of DentistrySelf Defense Forces Kure HospitalHiroshimaJapan

Personalised recommendations