Oral Presentation ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Viewing early life without labels: optical approaches for imaging the early embryo (#194)

Darren JX Chow 1 2 3 4 , Cheow Yuen (Tiffany) Tan 1 2 3 , Avinash Upadhya 1 3 4 5 , Megan Lim 1 2 3 4 5 , Kishan Dholakia 1 4 5 6 , Kylie R Dunning 1 2 3 4
  1. University of Adelaide, Adelaide, SA, Australia
  2. Robinson Research Institute, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
  3. Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, South Australia, Australia
  4. Centre of Light for Life, The University of Adelaide, Adelaide, SA 5005, Australia
  5. School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
  6. School of Physics and Astronomy, University of St Andrews, St Andrews, North Haugh, Scotland

Current approaches for evaluating embryo quality, such as subjective morphological observation and invasive biopsy, often fail to predict live birth in clinical IVF. The development of an accurate and non-invasive method to assess embryo quality would likely improve IVF success. Light-based technologies can fulfill this need[1]. We have previously shown that 2D imaging of fluorescent metabolic co-factors at the cellular scale – in the absence of exogenous tags or stains – can non-invasively detect embryo quality[2]. This 2D imaging approach is limited to a single plane. To be of value to the field such information needs to be captured rapidly in three dimensions (3D).

Here we employ innovative optical approaches that, for the first time, reveal developmentally important information within the embryo in 3D and in a spatio-temporal manner. Specifically, we used digital holographic microscopy to measure changes in refractive index (i.e. how the path of light changes as it passes through cells) as well as hyperspectral light-sheet microscopy to reveal dynamic changes in metabolism during development.

Using digital holographic microscopy, we found a significant difference in refractive index between embryos with high and low developmental potential (n = 4 independent experimental replicates; P<0.05). Differences in refractive index were in the order of 10-3, demonstrating the very high sensitivity of this approach. Using hyperspectral light-sheet microscopy to capture cellular autofluorescence, we were able to generate metabolic intensity maps of developing embryos in 3D, with significant shifts in metabolism detected across preimplantation development (n=3 independent replicates; P<0.05). Importantly, we confirmed that both forms of imaging are safe: embryo developmental competence between imaged and non-imaged embryos was comparable (P>0.05).

Collectively, these optical approaches, which operate without stains or exogenous tags, are a major advance towards developing an accurate and non-invasive diagnostic for embryo quality assessment, with implications for enhancing IVF outcomes.

  1. Darren J X Chow, Tiffany C Y Tan, Avinash Upadhya, Megan Lim, Kishan Dholakia, Kylie R Dunning, Viewing early life without labels: optical approaches for imaging the early embryo, Biology of Reproduction, 2024, 110(6): 1157–1174, DOI: 10.1093/biolre/ioae062
  2. Tiffany C Y Tan, Saabah B Mahbub, Jared M Campbell, Abbas Habibalahi, Carl A Campugan, Ryan D Rose, Darren J X Chow, Sanam Mustafa, Ewa M Goldys, Kylie R Dunning, Non-invasive, label-free optical analysis to detect aneuploidy within the inner cell mass of the preimplantation embryo, Human Reproduction, 2022, 37(1): 14–29, DOI: 10.1093/humrep/deab233