Figure 5.

SDS-PAGE and immunoblot analysis of proteins from serum adsorbed to chemically modified Si beads. Serum proteins adsorbed to untreated (Si) and oxidized silica beads (SiO₂) as well as to beads modified with 7 chemical functionalities were eluted from the silica bead surface by heating in SDS. Equal volumes of eluates were separated by SDS-PAGE. The original serum that was used for adsorption was run for comparison (first lane). Proteins in the gel were stained with Coomassie blue. Pink bands, generated by the staining of glycoproteins with periodic acid–Schiff stain, were not visible in the gel due to a general lack of densely glycosylated proteins in serum. Nitrocellulose transfers from gel replicates were probed with antibodies against fibronectin (FN), albumin (ALB), immunoglobulin A heavy chain (IGHA), immunoglobulin G F(ab)2 portion (IgG), and zinc-α2-glycoprotein (ZAG). Bound primary antibodies were detected with Alexa Fluor 488–tagged IgG secondary antisera.