Fluorescence sensor array for non-contact measurement of oxygen consumption rate of single oocyte on a microfluidic chip

Quality evaluation of oocyte and embryo has become one of the most important issues for many biomedical applications such as domestic animals and fertilization treatment. We developed measurement of oxygen consumption rate of individual oocyte by indirect fluorescence measurement using fluorescence oxygen sensor array having stripe-shape on a microfluidic chip. The fluorescence oxygen sensor was made of the mixture of photo-crosslinkable resin, polyethylene glycol diacrylate (PEG-DA) and Tris (2, 2´-bipyridyl) dichloro ruthenium (II) hexahydrate (Ru(bpy)₃Cl₂). The sensor was patterned to stripe-shape in the polydimethylsiloxane using photofabrication and molding technique. Oxygen concentration around the oocyte was distributed according to spherical diffusion theory because of similar oxygen permeability of polydimethylsiloxane and that of medium. The sensor array detects two-dimensional distribution of oxygen concentration and oxygen consumption ratio of the oocyte is calculated by image processing and Fick´s low. We demonstrated non-contact measurement of oxygen consumption ratio of single mouse oocyte on a microfluidic chip (0.59 ± 0.03 fmol/s).