Isolation & Characterization of Stable Exosomes in a Topical Cosmetic Formulation

BACKGROUND Skincare products that improve skin quality appearance via cosmetic active ingredients are of immense interest to combat signs of skin aging. A human fibroblast–conditioned medium containing growth factors, cytokines, and soluble extracellular matrix (ECM) proteins has also been found to contain exosomes, spherical nanovesicles involved in cellular communication, which may play a role in skin rejuvenation. OBJECTIVE To isolate and characterize exosomes in a topical cosmetic skincare formulation containing human dermal fibroblast–conditioned media. MATERIALS AND METHODS Exosomes were isolated via ultracentrifugation and size exclusion chromatography; characterized using Nanoparticle tracking analysis to assess exosome size, number, and distribution; transmission electron microscopy to visualize exosome structure and morphology; and multiplex ELISA to quantify exosome surface markers. An in vitro comparator gene expression analysis was conducted for ECM genes. RESULTS Nanoparticle tracking analysis indicated peak particle size at 150 nm and a concentration of 7.6E + 10 particles/mL. Transmission electron microscopy showed spherical structures with a size consistent with exosomes. Multiplex ELISA confirmed CD9, CD63, and CD81 expression. Gene expression analysis showed greater expression of ECM genes in a human skin model after topical cosmetic skincare application compared to similar products. CONCLUSION The topical cosmetic skincare formulation contains intact exosomes enriched with exosome-specific surface marker proteins.