We are just about ready to infect the cells with virus that will enable us to count the number of exosomes. The virus we have delivers both the marker and a resistance to an particular antibody, so once we let the virus settle, we can treat the cells with the antibody, and all of the cells not infected with the virus will die. This way, the only exosomes we will count will be produced by the cells infected with the virus. We changed our plan a little though, and instead of choosing the cell lines before infecting them, we are going to infect them first and choose the best cells lines after counting the exosomes produced. This way, we can bypass the necessity of exosome-free media.

On a different note, I think I should explain what exosomes actually are. They were discovered relatively recently, and were thought to be just little garbage cans of the cells. But in 1996, they were discovered to also function as a type of intercellular communication. They could be packaged with anything from proteins to digested pathogens to bits of RNA, all of which can get transferred and integrated with other cells. They ar involved in maintaining the immune system, although they can cause both beneficial and harmful effects. They are also have the same relationship with cancer, sometimes hindering and sometimes helping its progression. They often have receptors on their membrane that correspond to different types of cells that they communicate with. Occasionally, they will carry in them the necessary component to trigger apoptosis (cell death) in the receiving cell.