One-Step Synthesis of PEGylated Gold Nanoparticles with Tunable Surface Charge

Figure 4

SERS analysis: SERS spectra (employing the 785 nm laser line) of AuNPs coated with PEG200 (A), PEG400 (B), PEG1500 (C), PEG4000 (D), PEG6000 (E), PEG10000 (F) and PEG20000 (G). Raman spectrum of the pure PEG200 (H). The spectra were shifted for clarity. Some specific vibrational bands of PEG molecules attached to the gold nanoparticles are clearly visible. The SERS signal is sensitive to PEG molecular chain length.