KAIST develops label-free imaging technology to boost IVF success rates

Korean researchers have developed a foundational technology that can accurately select eggs and embryos to improve in vitro fertilization success rates for infertility treatment.

Lee Jeong-ha, a postdoctoral researcher in the laboratory of Professor Park Yong-keun of KAIST's Department of Physics, received the Basic Science Award in the poster presentation category at the 2026 annual meeting of the European Society of Human Reproduction and Embryology — the world's largest reproductive medicine conference — in recognition of the research, KAIST announced Tuesday.

The research team applied holotomography — a technique that uses light refraction data to image the interior of living cells in three dimensions without causing damage — to the field of infertility treatment. The technology enables non-invasive 3D quantitative analysis of changes in live eggs and embryos over time and demonstrates the potential of a next-generation assessment method capable of predicting developmental viability at an early stage.

In IVF procedures, the selection of eggs and embryos is the critical factor determining the likelihood of a successful pregnancy. However, because eggs and embryos are the very cells transferred to the patient, conventional analysis methods using dyes or fluorescent markers — which can affect the cells — are difficult to apply.

Current assessment methods are largely limited to qualitative evaluation based on two-dimensional imaging and the experience of embryologists. This is why demand for more objective, quantitative assessment technology has consistently grown.

To overcome these limitations, the research team applied holotomography. The technique is label-free — requiring no dyes or fluorescent markers — and works by measuring the degree to which light refracts as it passes through a cell, producing a three-dimensional image of the cell's internal structure without causing damage. It also allows quantitative measurement of the refractive index, which varies according to the density and composition of intracellular material, enabling analysis of even subtle structural changes within the cell.

The research team used holotomography to analyze the internal structures of eggs and embryos in three dimensions while keeping them alive and intact. Through mouse model experiments, the team confirmed that a range of biophysical data obtained during analysis can be used to predict developmental potential at an early stage. The findings also point to the possibility of moving beyond conventional morphological assessment — which focuses primarily on the external shape and size of cells — toward a new egg and embryo evaluation technology that combines objective quantitative data with AI analysis.

The study was conducted as a joint industry-academia-hospital research project involving KAIST's Department of Physics, the Infertility Center at Bundang CHA Hospital, the UK's Avenue Clinic and Tomocube. It represents a prime example of convergence research, applying advanced optical technology developed in fundamental physics to the clinical field of infertility treatment.

The most significant potential application lies in enabling more objective assessment of eggs and embryos in clinical IVF settings. Currently, embryologists often evaluate the shape and developmental status of eggs and embryos by examining two-dimensional microscope images. If sufficient clinical validation is carried out, three-dimensional refractive index data obtained through holotomography could be used alongside conventional morphological assessment to support more comprehensive evaluation of egg and embryo condition.

"We are currently conducting validation using human cells, and we will continue our research to develop this into an objective and accurate egg and embryo assessment technology that can contribute to improving infertility treatment success rates," said Professor Park.