| AVS 54th International Symposium | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS2+BI-ThA |
| Session: | Plasmas in Bioscience |
| Presenter: | L. Mayorga, University of Washington |
| Authors: | L. Mayorga, University of Washington R. Michel, University of Washington D.G. Castner, University of Washington T.A. Horbett, University of Washington |
| Correspondent: | Click to Email |
Antibody binding and ToF-SIMS were used to probe the conformation of fibrinogen (Fg) adsorbed to low and high fouling surfaces, including tetraglyme and FEP. Fg on implants plays a key role in the foreign body response (FBR) by mediating the adhesion of monocytes via the Mac-1 integrin.1 PEO-like tetraglyme coatings generated via radio frequency glow discharge plasma display ultra-low Fg adsorption (ΓFg < 10 ng/cm2) from low concentration blood plasma solutions and low monocyte adhesion.2 However, subcutaneously implanted tetraglyme still exhibits FBR encapsulation. With 3 mg/ml Fg in buffer (with tracer amounts of 125I-Fg added), ΓFg increased to 60 ng/cm2 on tetraglyme and 800 ng/cm2 on FEP. Nonetheless, the actual amount of ΓFg on glyme surfaces under any of the conditions tested is not enough to fully account for the observed monocyte adhesion in vitro. The Fg on glymes was relatively low, but adhesion was relatively high, suggesting that Fg might be in a more potent state on the glymes. To understand the role of Fg conformation in mediating monocyte adhesion, we used a monoclonal antibody to measure the degree of monocyte binding site (γ 377-395) exposure on adsorbed Fg. Epitope exposure per ng of adsorbed Fg was highest on low-fouling tetraglyme samples pre-adsorbed with low concentration Fg. In addition, ToF-SIMS was used as in previous studies3 to characterize the conformation of Fg adsorbed to the tetraglymes. By pairing these two different approaches to study the conformation of adsorbed Fg, we will be able to relate surface analysis results with cell and protein binding data, which will allow us to better understand protein-cell interactions in the FBR.
1Hu W-J, Eaton JW, and Tang L. Molecular basis of biomaterial-mediated foreign body reactions. Blood 2001; 98(4): 1231-1237.
2Shen MC, Martinson L, et al. PEO-like plasma polymerized tetraglyme surface interactions with leukocytes and proteins: in vitro and in vivo studies. J. Biomater. Sci. Polymer Edn. 2002; 13(4): 367-390.
3Michel R, Pasche S, Textor M, and Caster DG. Influence of PEG Architecture on Protein Adsorption and Conformation. Langmuir 2005; 21: 12327-12332.