Therapeutic cargo properties of isolated exosomes
The cargo properties of the isolated exosomes from different methods
were investigated using quercetin-loaded exosome mixtures on
pre-cultured and doxorubicin-induced senescent neonatal human dermal
fibroblasts. The results show no significant differences in relative
β-galactosidase activity between 160μM of free quercetin compared to
80μM quercetin loaded exosomes isolated by SEC (P>0.05) and
TEI (P>0.05) (Figure 5), but significantly higher than the
quercetin loaded with IP and exosomes alone. This indicates the
potential increase (almost doubling) of the intracellular concentration
of quercetin loaded in exosomes isolated by SEC and TEI in par with that
of 160μM free quercetin. Compared to negative control, all isolated EVs
loaded with quercetin significantly increased cell viability (Figure 6).
However, quercetin loaded into TEI isolated exosomes showed a
significantly higher cell viability percentage than the other two
isolation methods. The viability is similar to that of the 160μM free
quercetin and that of 150μM resveratrol, a potent antioxidant used as a
positive control in this experiment. This finding confirms the concept
of exosome’s ability in increasing bioavailability as well as the
reliability of TEI as the most suitable exosome extraction method.
Therefore, TEI extraction method was selected as the most suitable
method and, thus, used for the subsequent in vivo testing.