Cargo packaged into exosomes is tightly linked to the behaviour of the cell releasing them. eg a stressed cell would release exosomes with a different protein and RNA composition as opposed to when it is not stressed. I would like to know that apart from passage number ,cell seeding density and cell culture conditions (ph , temp , % CO2 , humidity) what else should be taken into consideration in order to make the cells behave consistently on sub - culturing so that they release qualitatively uniform exosomes every time. Or what factors affect cell behaviour in vitro.