Fig. 2: Optimization of aptamer concentrations.

a Measured current values for different CD63 concentrations that are used for the modification of microelectrodes. b Gel electrophoresis results for investigating the influence of initiator (I) concentrations on HCR. Lanes 1 and 12 are for DNA ladder markers. Lanes 2-5 are H1, H2, I, EpCAM, and a mixture of H1, H2, and EpCAM, respectively. Lanes 7-10 are for four different initiator concentrations 1.0, 0.5, 0.2, and 0.01 μM in solutions with 1 μM H1 and 1 μM H2, respectively. Lane 11 is for the mixture of I, H1, H2, and EpCAM.