Figure 3

In vitro stability of NPs. Size stability of NPs in various solutions: (A) 10 mM PBS, (B) 10% (v/v) FBS, and (C) 10% (v/v) human serum. Sizes of all NPs, except PK NPs, were stable in PBS over 9 days of incubation. LPK NPs demonstrated superior stability compared to PK NPs in the three solutions. In both FBS and human serum, sizes of all NPs increase more quickly compared to that in PBS. The inserts show antigen release from NPs within 10 h of incubation. Double asterisks indicate that the size of NPs at this point was significantly higher compared to that at 0 h (p value <0.05).