GNPs and Silica coated GNPs were analyzed using Nanosight NS300 (Malvern Panalytical, Malvern, UK). Videos were analyzed by the in-built NanoSight Software NTA 3.4 Dev Build 3.2.16. The Camera type, Camera level, and Detect Threshold were sCMOS, 9 and 5, respectively for 80 nm nanoparticles and 11 and 5 respectively for 40 nm nanoparticles. The number of completed tracks in NTA measurements was 5 (a 60 second movie was registered for each measurement). Samples were diluted in MQ water to a final volume of 1 mL. The ideal particle concentration was assessed by pre-testing the optimal particle per frame value (20-100 particles per frame).