4.6. Nanoparticle stability test

Freshly prepared NPs solution was diluted with PBS to test its stability in the presence of salt, and diluted with DI water 10, 100 and 500 fold to test its stability against dilution. For serum stability test, 1.0 ml of NPs solution was diluted with 1.0 ml FBS. The size and distribution of NPs were characterized by DLS. For different pH stability, 100 μL NPs solution was diluted with PBS 7.4, PBS 6.5 or 10 % FBS-containing PBS 7.4 buffer for 10-fold and tested the size and distribution of NPs by DLS.