On-chip enucleation of an oocyte by untethered microrobots

Akihiko Ichikawa, Shinya Sakuma, Masakuni Sugita, Tatsuro Shoda, Takahiro Tamakoshi, Satoshi Akagi, Fumihito Arai

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


We propose a novel on-chip enucleation of an oocyte with zona pellucida by using a combination of untethered microrobots. To achieve enucleation within the closed space of a microfluidic chip, two microrobots, a microknife and a microgripper were integrated into the microfluidic chip. These microrobots were actuated by an external magnetic force produced by permanent magnets placed on the robotic stage. The tip of the microknife was designed by considering the biological geometric feature of an oocyte, i.e. the oocyte has a polar body in maturation stage II. Moreover, the microknife was fabricated by using grayscale lithography, which allows fabrication of three-dimensional microstructures. The microgripper has a gripping function that is independent of the driving mechanism. On-chip enucleation was demonstrated, and the enucleated oocytes are spherical, indicating that the cell membrane of the oocytes remained intact. To confirm successful enucleation using this method, we investigated the viability of oocytes after enucleation. The results show that the production rate, i.e. the ratio between the number of oocytes that reach the blastocyst stage and the number of bovine oocytes after nucleus transfer, is 100%. The technique will contribute to complex cell manipulation such as cell surgery in lab-on-a-chip devices.

Original languageEnglish
Article number095004
JournalJournal of Micromechanics and Microengineering
Issue number9
Publication statusPublished - Sept 1 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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