Suspension culture in a T-flask with acoustic flow induced by ultrasonic irradiation

Genichiro Fujii, Yuta Kurashina, Yusuke Terao, Tetsushi Azuma, Akira Morikawa, Kazuhide Kodeki, Osamu Takahara, Kenjiro Takemura

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Suspension culture is an essential large-scale cell culture technique for biopharmaceutical development and regenerative medicine. To transition from monolayer culture on the culture surface of a flask to suspension culture in a bioreactor, a pre-specified cell number must first be reached. During this period of preparation for suspension culture, static suspension culture in a flask is generally performed because the medium volume is not large enough to use a paddle to circulate the medium. However, drawbacks to this static method include cell sedimentation, leading to high cell density near the bottom and resulting in oxygen and nutrient deficiencies. Here, we propose a suspension culture method with acoustic streaming induced by ultrasonic waves in a T-flask to create a more homogeneous distribution of oxygen, nutrients, and waste products during the preparation period preceding large-scale suspension culture in a bioreactor. To demonstrate the performance of the ultrasonic method, Chinese hamster ovary cells were cultured for 72 h. Results showed that, on average, the cell proliferation was improved by 40% compared with the static method. Thus, the culture time required to achieve a 1000-fold increase could be reduced by 32 h (a 14% reduction) compared with the static method. Furthermore, the ultrasonic irradiation did not compromise the metabolic activity of the cells cultured using the ultrasonic method. These results demonstrate the effectiveness of the ultrasonic method for accelerating the transition to large-scale suspension culture.

Original languageEnglish
Article number105488
JournalUltrasonics Sonochemistry
Publication statusPublished - 2021 May


  • Acoustic streaming
  • Cell activity
  • Cell proliferation
  • Chinese hamster ovary
  • Suspension culture
  • Ultrasonic

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Radiology Nuclear Medicine and imaging
  • Inorganic Chemistry
  • Acoustics and Ultrasonics
  • Environmental Chemistry
  • Organic Chemistry


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