Figure 4

(a) Real-time measurements of the resonance frequency after consecutive injections of Zn2+/C4diP solutions at different ratios, measurement times 5 minutes each. (b) The average of stiffness from Fig. 2a during the last 40 seconds of the injection, at each injected Zn2+/C4diP ratio. In blue is shown the stiffness response of SNTs in the absence of DNA.