Fig. 3. Investigation of cooperative binding of the interparticle relatively motional DNA walker. (A) The fluorescence increases of the DNA walker in the presence of different target concentrations as a function of reaction time, in which curves are drawn by nonlinear fitting with the ExpDec2 function. (B) Fluorescence changes of the DNA walker in the first 30 min at various target concentrations. (C) Initial reaction rate of the DNA walker at varying target concentrations. The error bars are the standard deviation of three measurements. (D) Schematic diagram of operation of the DNA walker response to low or high target concentration.