Representative bright field microscopy images of PBMC on modified surfaces. The images were taken on PEG-modified surfaces (A-C), piranha treated cover slips (D) and bovine serum albumin (BSA) covered glass (E) after 37–54 min (representative of 5 repeats for A-C and of 3 for D and E). PEGylation of glass cover slips inhibits spreading of PBMC independent of the anticoagulant used (citrate in A, EDTA in B and heparin in C). Both PBMC and platelets are spreading extensively and irreversibly on piranha treated glass (D). On bound BSA (E), some cells are spreading with or without migration, while most of the PBMC stay localized without spreading. Platelets attach to neither the PEG surfaces (A-C) nor the BSA modified surface (E), but do though strongly on glass (not visible on this section).