Figure 2.

Characterization of GNPs. (a) Schematic diagram of GNP functionalized with both PEG polyether and RGD peptides to create the GNP_PEG-RGD complex used in this study. (b) TEM image of GNPs with a core size of 10.9 nm (± 1.2 nm). Scale bar is 50 nm. (c,d) Distributions of the hydrodynamic diameters, and ζ-potentials for pure GNPs, GNP_PEG, and GNP_PEG-RGD, respectively. GNP_PEG is GNP functionalized with PEG, which acts as a stabilizing agent; GNP_PEG-RGD is a GNP functionalized with both PEG and RGD, which enhances GNP uptake. (e) Table with the peak absorption wavelengths, hydrodynamic diameters, and mean ζ-potentials for pure GNPs, GNP_PEG, and GNP_PEG-RGD. Note: the error is represented by the standard deviation over three different measurements.