Schematic representation of the mimic miRNA Au NPs. In (A), the typical endogenous miRNA structure (miRNA: miRNA*) with one or more bulges is shown. Only the mature miRNA strand, in red, is known to be involved in downstream gene regulation pathways. In (B), the scheme and sequences of the mimic miRNA-205 Au NP (upper) and mimic miRNA-20a Au NP (lower) attached to 13 nm gold nanoparticle (red hemisphere) are depicted. In both cases, the sense strand is attached to the gold surface through the adsorption of alkyl thiol on gold. The red letters represent mature miRNA sequences.