Bioprocessing of Mesenchymal Stem Cells and Their Derivatives: Toward Cell-Free Therapeutics

Figure 1

Types of extracellular vesicles and their identifying characteristics. Exosomes, with diameters ranging from 30 to 200 nm, are formed by the inward budding of multivesicular bodies (MVBs), which then fuse with the plasma membrane to be released into the extracellular environment. Exosomes are classified by tetraspanins CD9, CD63, and CD81 and the proteins Alix and TSG101 involved in MVB biogenesis. Microvesicles, also referred to as ectosomes, are larger with diameters from 50 to 1000 nm and bud directly from the plasma membrane. Microvesicles encompass identifying markers CD40, integrin, and selectin. Apoptotic bodies range from 500 to 2000 nm and encompass fragments of dead or dying cells. These are characterized by the presence of histones and annexin V.