Fig. 4

Optimization of the plasmonic NP-graphene interface for Cyt c-mediated PRET and ROS detection. a, b Cyt c-mediated PRET signals measured using SNP (a) and GNP (b) with increasing number of graphene layers. Solid lines and dotted lines indicate the probe spectra in the absence and presence of Cyt c, respectively. c, d Plots showing the change in depth of the quenching dip at 550 nm measured using SNP (c) and GNP (d) with increasing number of graphene layers. e H₂O₂ concentration-dependent changes in the spectral quenching dip of the SNP probe (left, G0-SNP) and SNP probe covered with two layers of graphene (right, G2-SNP). f Calibration curves for H₂O₂ obtained with G2-SNP (red) and G0-SNP (black). g Illustration showing the relationship between electron movement through the interface and the resulting PRET signal