Microfluidic On-Chip Assay for Quantifying Blastoid Adhesion to Endometrial Epithelium

The ability of the endometrium to accept and support embryo implantation is crucial, but factors influencing this process remain elusive. This method aims to obtain precise quantitative information on factors causally affecting the initial stages of embryo implantation. We developed a personalized implantation-on-chip platform using in vitro models of the endometrium (organoids) and the embryo (blastoids) to quantify functional embryo attachment. Here, we describe a microfluidic platform for precisely assessing functional receptivity of endometrial epithelium through blastoid adhesion. Endometrial organoids were expanded and transformed into epithelial monolayers within custom-made microfluidic chips. These chips were then infused with large numbers of blastoids (>100) per chip. Followed after 48 h of co-culture, blastoids were exposed to a controlled stepwise increasing flow rate (50, 100 and 400 µL/min), while the rate of adhered blastoids was precisely measured from image-based readouts. Our method offers a robust platform for studying endometrial epithelial receptivity and testing therapeutic interventions with potential impact for infertile patients.