Fig. 1. Validation of the PNA microarray-based fluorometric assay for EGFR mutation screening. (A) PAGE analysis of the RCAP of EGFR mutation (lane a), EGFR wildtype (lane b) and random DNA (lane c). The RCAP without target EGFR sequence (lane d) and the RCAP of EGFR mutation without phi29 DNA polymerase were also included as negative controls. (B) PAGE analysis of the ligation product and the RCAP of EGFR mutation (lane c and d) and EGFR wildtype (lane g and h). EGFR mutation (lane a), EGFR wildtype (lane e) and padlock probe (lane b and f) were also included as controls. Marker: 20 bp molecular weight marker DNAs. The RCAPs were analyzed by 10% PAGE in 1× TBE buffer and visualized with gel red staining. (C) Fluorescence emission spectra and (D) fluorescence intensity (648 nm) responses of Cy5-labeled F-DP (1 μM) in the absence and presence of RCAP of EGFR mutation, EGFR wildtype or random DNA after incubation with 10 μg mL⁻¹ GO. The fluorescence of F-DP itself was also included as a control.