961216.fig.003
Figure 3: Raman spectrum of solid pure L-ascorbic acid (scaled by factor 0.25)(spectrum a). SERS spectrum of individual gold nanospheres in solution recorded under NIR excitation (spectrum b). SERS spectra of PEG-GENs obtaine with increasing volumes: 20 μL (spectrum c), 50 μL (spectrum d), and 100 μL (spectrum e) mPEG-SH, recorded under NIR excitation.