Figure 4.

(a) UV–vis spectra of AgNPs-C1 suspended in water (black) or in human serum for 1 h (blue), then centrifuged and resuspended in water. This centrifugation/resuspension step was necessary due to the large absorbance of human serum between 300 and 500 nm. (b) UV–vis spectra of AgNPs-C1 suspended in water before (black) and after drying at 70 °C for 4 h and resuspended in pure water (green). Inset shows pictures of the AgNPs-C1 before drying, after drying, and then resuspended. (c) ATR-FTIR spectra of AgNPs-C1 before (black) and after (blue) conjugation of H₂N-PEG-OCH₃.