The AgNPs batches used in the experiments were periodically characterized
through measurement of pH and silver ion content in solution,
and determination of the position, area (A) and Wh/2 in a UV-Visible
spectrum (Fig. S1). Other techniques such as transmission electron microscopy
(TEM) and Flow-field flow fractionation (F-FFF) were also
used to determine AgNP size (Figs. S2–S3 and more details in the SI).