Fig. 4

Fluorescent responses of the dual-emission BY-CD-based ratiometric assay at different concentrations of microRNA-21 from 0.15 fM to 2.46 pM, Inset: linear relationships of ΔF₅₄₀/ΔF₄₁₀ versus log C (microRNA-21) and logarithmic relationships of ΔF₅₄₀/ΔF₄₁₀ versus target concentration (microRNA-21) (A); Selectivity of the dual-emission BY-CD-based assay toward microRNA-21 sensing. The concentrations of microRNA-21 (T-21), and interferences, including microRNAs-155 (T-155), one base-mismatched microRNA-21 (M-21), and one base-mismatched microRNA-155 (M-155) were all 0.3 pM (B); Fluorescent responses and the linear relationship between ΔF₅₄₀/ΔF₄₁₀ and the concentration of microRNA-21 extracted from of the MCF-7 cells from 3000 to 45,000 (cell mL⁻¹) (C)