Fertilization is the founding event of life. Its success requires the fusion of one—and only one—sperm with an egg, as fusion of multiple sperm leads to pathological polyspermy. Despite decades of research, the mechanisms governing gamete fusion and subsequent block to polyspermy remain poorly understood. Advanced real-time imaging approaches of the gamete contact zone before and after fusion are essential to resolve the sequence of events underlying sperm–egg fusion and the establishment of the block to polyspermy. However, under physiological in vitro fertilization conditions, the large number and high motility of sperm contacting the zona pellucida (ZP), a glycoprotein envelop surrounding the egg, limit the applicability of high-resolution real-time imaging. The aim of the internship is to overcome this limitation by creating a biomimetic microfluidic environment for gametes that reproduces physiological conditions while allowing real-time imaging. The intern will make and test the first prototypes of a new microfluidic device, with which we will control the timing and location at which a sperm reaches the egg plasma membrane while immobilizing the egg to enable spatiotemporal imaging of the interaction site. The egg ZP will be removed and functionally replaced by a microfluidic valve that regulates sperm access and constrains sperm head movement. This chip will open avenue to study the gamete fusion by imaging relevant fusion protein reorganization on the gametes.