Characterization of exosomes from hypoxia-activated human amniotic membrane mesenchymal stem cells.

Objectives: ) conditions on the characteristics of amniotic membrane-derived mesenchymal stem cells (AM-MSCs) and their exosomes. Materials and Methods: AM-MSCs were isolated, confirmed, and cultured under normoxic and hypoxic conditions. Exosomes were extracted from AM-MSCs and assessed for morphological characteristics (size/distribution/surface topography), structural properties (aggregation/colloidal particle behavior/surface charge/stability), chemical features (functional groups/ionic interactions), biological capacities (total protein concentration), and biocompatibility (microbiological quality/cytotoxicity/irritation/sensitization). Results: ≤0.05). The total protein concentration in the hypoxic group was significantly higher than in the normoxic conditions (5.003 mg/ml vs. 4.109 mg/ml, representing a 1.22-fold increase) (P≤0.01). Exosomes extracted under normoxic and hypoxic conditions demonstrated acceptable biocompatibility with no signs of cytotoxicity, irritation, sensitivity, or microbial contamination. Conclusion: Hypoxic preconditioning enhances the yield and physicochemical stability of AM-MSC-derived exosomes, due to their unique composition and functional properties.