Revolutionizing Embryo Selection: Agarose Dishes Enhance IVF Success
Selecting the healthiest embryo is a critical yet uncertain step in in-vitro fertilization (IVF), with success rates often below 33 percent. Embryologists typically rely on visual inspection of embryos under a microscope in flat dishes. Newer "well-of-the-well" (WOW) dishes, which use 3D microwells, offer a more natural environment for embryo development but pose optical challenges.
The plastic and silicone materials commonly used for these wells bend light differently than the surrounding culture medium, leading to blurred images, warped edges, and obscured details.
The "Optically Invisible" Solution
Researchers at Vanderbilt University developed a solution by fabricating WOW dishes from agarose, a hydrogel primarily composed of water. Agarose has an optical refractive index nearly identical to the culture medium, allowing light to pass through without significant bending or scattering.
This makes the 3D structure almost optically "invisible," enabling microscopes to capture sharp, undistorted images.
Rigorous Optical Verification
The team tested their agarose dishes against traditional PDMS versions. Optical assessments using tiny microspheres showed that ridges from the manufacturing process, which visibly warped images in PDMS dishes, nearly disappeared in agarose dishes, resulting in clearer details. A Shack–Hartmann wavefront sensor confirmed that while PDMS dishes introduced pronounced high-order aberrations, agarose dishes produced wavefront patterns almost identical to those seen through a standard flat petri dish, indicating minimal optical interference.
Promising Results for Embryo Development
Further testing involved culturing mouse embryos in the agarose dishes. The embryos showed normal development, comparable to established culture systems. Microscopy images clearly resolved internal embryonic structures, which are important for grading.
This development removes a significant barrier to the adoption of 3D microwell culture, allowing embryologists to use dishes that promote healthier growth while maintaining clear visibility. This advancement could enhance the accuracy of embryo selection and potentially contribute to higher IVF pregnancy rates.