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.