3.4 Biocompatibility of peptides and RS-NC
Cytocompatibility of RS and RT peptides was assessed using the CCK-8
assay of MDA-MB-231 and HDFn cells (Fig. 7). First, the RS peptide did
not show any significant decrease of cell viability in all peptide
concentrations for both cells. Also, the RT peptide did not represent a
statistically significant decrease of cell viability in most peptide
concentrations except 15 μM for MDA-MB-231 cells (p -value =
0.032).
Biocompatibility of RS-NC was tested by histological analysis and
inflammatory cytokine levels of RS-NC-injected Balb/c mouse’s back skin
intradermally (Fig. 8). First, skins injected by PBS and RS-NCs with
negative control siRNAs were compared using H&E-stained histological
analysis (Fig. 8a). As a result, H&E-stained both skins maintained
similar thickness of dermis layer and did not represent any
morphological difference. Moreover, no tissue damage or inflammatory
infiltration was observed. Second, TNF-α and IL-6 levels of solubilized
skin tissue were measured by ELISA analysis (Fig. 8b). Both cytokine
levels did not represent a statistically significant difference between
PBS and RS-NCs with negative control siRNAs. In summary, RS peptide and
RS-NC were confirmed as cytocompatible and biocompatible.