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Figure 2: Plasmonic shift due to streptavidin and Biotin-PEG-Vn96 interactions. (a) Dependency of ∆λ on the concentration of streptavidin only. (b) Ratio of Biotin-PEG-Vn96 to Streptavidin. (c) Dependency of the shift of Au LSPR band on the concentration of MCF-7 exosomes. (d) Size distribution of MCF7 exosomes as obtained by Tunable Resistive Pulse Sensing (TRPS) measurements. (e) Exosomes with different sizes and shapes captured by Vn96 molecules. (f, g) SEM images of exosomes captured by gold nanoislands during the last step of the biosensing (exosomes are marked in circles).