Isolation of Extracellular Vesicles in Saliva Using Density Gradient Ultracentrifugation

This chapter describes a method for isolating human salivary extracellular vesicles (EVs) using density gradient ultracentrifugation. Standard protocols established for isolation of EVs from blood or a conditioned medium of cultured cells do not work for whole saliva, due to its viscosity. Therefore, procedures including a pretreatment step and utilizing iodixanol as a gradient material enable EVs to be concentrated to a 1.1 g/ml density. This protocol is compatible with both swing and angle rotors. By employing an angle rotor, which enables high g-force, the centrifugation time was reduced to 4 h from the 17 h required when using a swing rotor.