Dynamic Light Scattering (DLS) A Zetasizer Nano ZS (Malvern Panalytical, Malvern, UK) equipped with a 633 nm Helium-Neon laser was used for all DLS measurements. Nanoparticle hydrodynamic diameter and polydispersity index (PDI) were measured prior to and following recovery from incubation media (either PBS control or 10 %v/v FBS in PBS following 2-and 24-hour incubation). All measurements were performed using three independent replicates, with each replicate being measured five times. The hydrodynamic diameter was reported as the Z-average with associated standard error. This was performed using the zetasizer software (7.11) from Malvern Instruments. Electrophoretic Light Scattering ELS was performed to measure changes in the ζ-potential (mV) of polystyrene nanoparticles (dispersed in 2mM KCl) following recovery from incubation media, and the Smoluchowski model was used for data processing. All size and zeta potential measurements were performed at 25 °C. The mean (±standard error) for each sample was determined from five independent measurements. This was performed using the zetasizer software (7.11) from Malvern Instruments.