Q: We occasionally observe small particles under the microscope when culturing with protein supplemented media. What is the source of this particulate matter?
A: Protein supplements contain human source material which can develop particulate matter during storage. When using protein-supplemented media, it is not uncommon to have particles form over time as a result of multiple warming and cooling cycles during their shelf life. This type of particulate matter does not adversely affect the performance of the media or embryo development.