AVS 45th International Symposium
    Biomaterial Interfaces Group Monday Sessions
       Session BI-MoA

Paper BI-MoA3
Leukocyte Adhesion on Self-Assembled Thiol Monolayers under Flow

Monday, November 2, 1998, 2:40 pm, Room 326

Session: Cell Solid-Surface Interactions
Presenter: V.A. Tegoulia, University of Delaware
Authors: V.A. Tegoulia, University of Delaware
S.L. Cooper, University of Delaware
Correspondent: Click to Email
The effect of specific chemical functionalities on the attachment of neutrophils, one of the cells responsible for host response to biomaterials, was investigated using self-assembled monolayers (SAMs) containing different terminal groups. A surface modification was used to incorporate a zwitterionic phosphorylcholine group on one of the surfaces. Adhesion was studied on surfaces preadsorbed with fibrinogen or albumin, under well defined flow conditions using a radial flow chamber and automated videomicroscopy. The general formula for the thiols used was HS-(CH@sub 2@)@sub 10@-X, where X=CH@sub 3@, CH@sub 2@OH, COOH, COOCH@sub 3@ and CH@sub 2@(OCH@sub 2@CH@sub2@)@sub 3@OH (EG@sub 3@). The phosphorylcholinated monolayer (PC, X=CH@sub 2@PO@sub 4@CH@sub 2@CH@sub 2@N(CH@sub 3@)@sub 3@ was prepared by phosphorylation of the hydroxyl terminated SAM. Contact angle measurements, ellipsometry and X-ray photoelectron spectroscopy (XPS) were used to characterize the SAMs. The amount of adsorbed protein on the surfaces was quantified using radiolabelled fibrinogen and albumin. Neutrophils were isolated from fresh human whole blood. Contact angle measurements, ellipsometry and XPS confirmed the presence of the SAMs. Phosphorous and nitrogen were detected on the phosphonated SAM. Neutrophil attachment was found to be higher at the low shear rates. Cell adhesion was increased on the hydrophobic CH@sub 3@ and the anionic COOH terminated surface. Cells were more activated on the COOH surface. The presence of the EG@sub 3@ and the PC moieties led to very low cell adhesion.