2.5. Dynamic light scattering (DLS) characterization

DLS measurements were done using a Zetasizer Nano ZS (Malvern Instruments) with a 4 mW He–Ne laser (632 nm) at 25 °C. The sample was diluted in deionized water at a very low concentration and then sonicated for 1 h to ensure even nanoparticle distribution. 1 ml of each solution was deposited on a clear plastic cuvette. Data was obtained at 12.8° and 175° measurement angles and averaged over 12 scans.