Figure 3: UV-vis absorption spectra (a) and bar graph at 650 nm (b). The effect of each reagent was tested in the colorimetric system. MNPs@TMB@H2O2: red solid line, MNPs@TMB: blue solid line, MNPs@DNA@H2O2: red dashed line, MNPs@H2O2: blue dashed line, and TMB@H2O2: black dash line. The insets in (b) represent images of the well plates for the different colors in the five cases.