Fig. 2. Characterization of DNA-hybrid-gated UCNPs@UIO-66-NH2/DOX. (A) UV-visible absorption spectra, (B) upconversion luminescence spectra under excitation at 980 nM of different samples and UV-visible absorption of DOX, (C) zeta potentials of the nanoparticles, and (D) polyacrylamide gel electrophoresis for verification of strand displacement reaction (M: marker; lane 1: anchor-DNA; 2: capping-DNA; 3: miR-21; 4: DNA duplexes hybridized by anchor-DNA and capping-DNA; 5: mixed system of DNA duplexes and miR-21; 6: DNA duplexes hybridized by capping-DNA and miR-21).
