title: Enhanced mechanical damage to in vitro cancer cells by high-intensity-focused ultrasound in the presence of microbubbles and titanium dioxide.
abstract: OBJECTIVE
  To evaluate in vitro the feasibility of therapeutic high-intensity-focused ultrasound (HIFU) combined with microbubbles and titanium dioxide (TiO2).
  
  
  METHODS
  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/cm(2), and two pulses (0.5 s each) were sonicated for each cell sample (9 × 10(4) 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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Anatomy, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jonan, Fukuoka, 814-0180, Japan. k-tachi@fukuoka-u.ac.jp.
authors.forename: Katsuro
authors.initials: K
authors.lastname: Tachibana
authors.affiliation: Department of Anatomy, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jonan, Fukuoka, 814-0180, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Endo
authors.affiliation: Department of Anatomy, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jonan, Fukuoka, 814-0180, Japan.
authors.forename: Loreto B
authors.initials: LB
authors.lastname: Feril
authors.affiliation: Department of Anatomy, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jonan, Fukuoka, 814-0180, Japan.
authors.forename: Seyedeh Moosavi
authors.initials: SM
authors.lastname: Nejad
authors.affiliation: Department of Oral Surgery, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jonan, Fukuoka, 814-0180, Japan.|Department of Dentistry, Self Defense Forces Kure Hospital, 6-34, Showa, Kure, Hiroshima, 737-0027, Japan.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Oral Surgery, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jonan, Fukuoka, 814-0180, Japan.
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Narihira
authors.affiliation: Department of Oral Surgery, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jonan, Fukuoka, 814-0180, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kikuta
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000628:therapy*; D002470:Cell Survival; D005240:Feasibility Studies; D006801:Humans; D045423:Microbubbles; D009062:Mouth Neoplasms / Q000473:pathology* / Q000628:therapy*; D009369:Neoplasms / Q000473:pathology*; D013010:Sonication; D014025:Titanium / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects*
chemical_list: C009495:titanium dioxide; D014025:Titanium
keywords: Cell damage; High-intensity-focused ultrasound (HIFU); Microbubbles; Titanium dioxide