Fig. 4

Deposition of components of the mouse complement system on PNPs. The proteins adsorbed on PNPs were analyzed by LC-MS/MS and Western blot (WB) analyses. Immunoglobulins were quantified by LC-MS/MS (A) and the deposition of mouse IgG (B) and IgM (C) was also analyzed by WB (attended band at 50 kDa and 75 kDa, respectively). Components of the classical complement activation pathway were analyzed by LC-MS/MS analysis (D); the corresponding bands of C1q chains were visualized by WB (E, attended bands height: ~26 and 27 kDa). Proteins of the alternative pathway (F) deposited on particles were detected by LC-MS/MS analysis. LC-MS/MS data (n=4) are presented as abundance values (arbitrary values generated by mass spec peak integration) and are shown as boxplot with median value. uPNPs: untargeted nanoparticles; tPNPs: targeted nanoparticles; MS: mouse serum; empty: empty well