Selecting the healthiest embryo is a key step in in-vitro fertilization (IVF), but it remains challenging due to uncertainty in identifying which embryo will most likely result in a successful pregnancy. Globally, about 15 percent of couples experience infertility, and IVF success rates are often below 33 percent. Embryologists rely on microscopic imaging to assess embryos, looking for subtle visual cues such as cell division patterns and internal structures.
Recent research from Vanderbilt University, published in Biophotonics Discovery, addresses this challenge by introducing a new type of culture dish made from agarose hydrogel. Traditional "well-of-the-well" (WOW) dishes use plastics or silicone-based materials that can distort light, leading to blurred images and obscured details under the microscope. This optical interference forces embryologists to choose between better embryo development environments and clear imaging.
The team at Vanderbilt fabricated WOW dishes using agarose because its optical refractive index closely matches that of the liquid culture medium. This similarity allows light to pass through without significant bending or scattering, making the 3D structure nearly optically "invisible." As a result, microscopes can capture sharp and undistorted images of embryos.
In tests comparing agarose dishes with traditional PDMS versions, researchers used microspheres to evaluate image resolution and geometric accuracy. The PDMS dishes showed visible warping due to manufacturing ridges, while these distortions were nearly absent in the agarose dishes. A Shack–Hartmann wavefront sensor further confirmed that PDMS introduced complex optical aberrations, whereas agarose dishes produced wavefronts similar to those seen with standard flat petri dishes.
To ensure that the new material did not compromise embryo development, mouse embryos were cultured in the agarose dishes. The embryos developed normally and microscopy revealed sharply resolved internal features important for grading their quality.
According to the study's findings, "the agarose-based design allows embryologists to use dishes that promote healthier growth without sacrificing visibility." Researchers believe this approach could improve embryo selection accuracy and potentially increase pregnancy rates for IVF patients.
