Fig. 6From: Polyethyleneglycol diacrylate hydrogels with plasmonic gold nanospheres incorporated via functional group optimizationFT-IR spectroscopy of synthesized pristine Au/PEG-DA, lysine functionalized Au/PEG-DA, glutathione functionalized Au/PEG-DA, and thioglycolic acid functionalized Au/PEG-DA in a 4000–800 cm−1 range and b magnified 3300–1600 cm−1 range near peaks from –C=O and C–H bonds of PEG-DABack to article page