Figure 4. Operating curves showing specificity and sensitivity of the DNAzyme motor.

(a) Operating curves of the DNAzyme motor tested with the target DNA sequence and five variants of single-base mismatch. Sequences of the mismatch variants are shown in Supplementary Table 1. RSDs were 1.4–7.6%. (b) Operating curves of the DNAzyme motor in response to varying concentrations (0–500 pM) of the target miRNA. Different concentrations (0–500 pM) of the target miRNA were added into motor solutions each containing the equivalent of 230 pM AuNP. The solutions were incubated for 20 min to ensure the strand displacement reaction was completed. Then 500 μM Mn²⁺ was added into the solutions to activate the DNAzyme. The time at which Mn²⁺ was added is referred to as time 0. RSDs were 1.1–9.3%.