Vitrification within a nanoliter volume: oocyte and embryo cryopreservation within a 3D photopolymerized device

  • J Assist Reprod Genet. 2022 Sep;39(9):1997-2014. doi: 10.1007/s10815-022-02589-8.
Suliman H Yagoub  1  2  3 ,  Megan Lim  1  2  3 ,  Tiffany C Y Tan  1  2  3 ,  Darren J X Chow  1  2  3 ,  Kishan Dholakia  4  5  6 ,  Brant C Gibson  1  7 ,  Jeremy G Thompson  1  2  3  8 ,  Kylie R Dunning  9  10  11
Affiliations
  • 1. Australian Research Council (ARC) Centre of Excellence for Nanoscale BioPhotonics (CNBP), Adelaide, South Australia, 5000, Australia.
  • 2. School of Biomedicine, Robinson Research Institute, University of Adelaide, Adelaide, South Australia, 5005, Australia.
  • 3. Institute for Photonics and Advanced Sensing (IPAS), University of Adelaide, Adelaide, South Australia, 5000, Australia.
  • 4. School of Physics and Astronomy, University of St Andrews, North Haugh, Scotland, KY16 9SS.
  • 5. School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia.
  • 6. Department of Physics, College of Science, Yonsei University, Seoul, 03722, South Korea.
  • 7. School of Science, RMIT, Melbourne, VIC, 3001, Australia.
  • 8. Fertilis Pty Ltd, Adelaide, South Australia, 5005, Australia.
  • 9. Australian Research Council (ARC) Centre of Excellence for Nanoscale BioPhotonics (CNBP), Adelaide, South Australia, 5000, Australia. [email protected].
  • 10. School of Biomedicine, Robinson Research Institute, University of Adelaide, Adelaide, South Australia, 5005, Australia. [email protected].
  • 11. Institute for Photonics and Advanced Sensing (IPAS), University of Adelaide, Adelaide, South Australia, 5000, Australia. [email protected].
PMID: 35951146 DOI: 10.1007/s10815-022-02589-8
Abstract

Purpose: Vitrification permits long-term banking of oocytes and embryos. It is a technically challenging procedure requiring direct handling and movement of cells between potentially cytotoxic cryoprotectant solutions. Variation in adherence to timing, and ability to trace cells during the procedure, affects survival post-warming. We hypothesized that minimizing direct handling will simplify the procedure and improve traceability. To address this, we present a novel photopolymerized device that houses the sample during vitrification.

Methods: The fabricated device consisted of two components: the Pod and Garage. Single mouse oocytes or embryos were housed in a Pod, with multiple Pods docked into a Garage. The suitability of the device for cryogenic application was assessed by repeated vitrification and warming cycles. Oocytes or early blastocyst-stage embryos were vitrified either using standard practice or within Pods and a Garage and compared to non-vitrified control groups. Post-warming, we assessed survival rate, oocyte developmental potential (fertilization and subsequent development) and metabolism (autofluorescence).

Results: Vitrification within the device occurred within ~ 3 nL of cryoprotectant: this volume being ~ 1000-fold lower than standard vitrification. Compared to standard practice, vitrification and warming within our device showed no differences in viability, developmental competency, or metabolism for oocytes and embryos. The device housed the sample during processing, which improved traceability and minimized handling. Interestingly, vitrification-warming itself, altered oocyte and embryo metabolism.

Conclusion: The Pod and Garage system minimized the volume of cryoprotectant at vitrification-by ~ 1000-fold-improved traceability and reduced direct handling of the sample. This is a major step in simplifying the procedure.

Keywords
3D fabrication; Embryo; IVF; Metabolism; Oocyte; Photopolymerization; Vitrification.