have evaluated Mφ‐derived Exos for protecting the catalase molecules and delivering them to the brain for the treatment of Parkinson's disease (PD).[216] After the Exos were extracted from the culture media with centrifugation, their drug loading efficiency with various methods, including incubation at room temperature with or without saponin, repeated freeze–thaw cycles, sonication, and extrusion was evaluated. The gene discussed is CAT; the disease is Parkinson disease.