TY - JOUR
T1 - AFM measurements of interactions between the platelet integrin receptor GPIIbIIIa and fibrinogen
AU - Agnihotri, Aashiish
AU - Soman, Pranav
AU - Siedlecki, Christopher A.
N1 - Funding Information:
The authors would like to acknowledge financial support from the National Science Foundation (DMR-0804873), the Biomedical Engineering Institute at the Pennsylvania State University College of Medicine, and the Materials Research Institute at the Pennsylvania State University. We would also like to thank Dr. Lichong Xu for valuable technical discussions.
Copyright:
Copyright 2009 Elsevier B.V., All rights reserved.
PY - 2009/6/1
Y1 - 2009/6/1
N2 - Binding of receptor proteins on circulating platelets to fibrinogen adsorbed on a biomaterial surface is a critical event in the blood-material interactions and surface-induced thrombogenesis. In this work, the interactions between purified platelet membrane integrin GPIIbIIIa (αIIbβ3) and fibrinogen on model hydrophilic and hydrophobic surfaces were characterized by measuring ligand-receptor debonding forces by atomic force microscopy (AFM). Force profiles between AFM probes functionalized with platelet integrins and fibrinogen on these substrates showed multiple rupture events over large distances on both surfaces. On the hydrophobic surface, the rupture length range was 20-200 nm, whereas on the hydrophilic surface, the rupture length range was 20-400 nm. Rupture events in the force curves were found to arise from non-specific protein-protein interactions, mechanical denaturation of fibrinogen domains, as well as the specific ligand-receptor interactions between integrins and fibrinogen. Analysis of the distributions of the debonding forces was used to estimate the strength of single integrin-fibrinogen pair at different loading rates. For loading rates of 10-60 nN/s, the debonding strength of a single integrin-fibrinogen pair was found to be in the range of 50-80 pN and was independent of the underlying substrate. Results suggest that once the active platelet binding epitope in fibrinogen becomes exposed by surface adsorption, binding of the platelet membrane integrin receptor will be similar regardless of the material surface properties.
AB - Binding of receptor proteins on circulating platelets to fibrinogen adsorbed on a biomaterial surface is a critical event in the blood-material interactions and surface-induced thrombogenesis. In this work, the interactions between purified platelet membrane integrin GPIIbIIIa (αIIbβ3) and fibrinogen on model hydrophilic and hydrophobic surfaces were characterized by measuring ligand-receptor debonding forces by atomic force microscopy (AFM). Force profiles between AFM probes functionalized with platelet integrins and fibrinogen on these substrates showed multiple rupture events over large distances on both surfaces. On the hydrophobic surface, the rupture length range was 20-200 nm, whereas on the hydrophilic surface, the rupture length range was 20-400 nm. Rupture events in the force curves were found to arise from non-specific protein-protein interactions, mechanical denaturation of fibrinogen domains, as well as the specific ligand-receptor interactions between integrins and fibrinogen. Analysis of the distributions of the debonding forces was used to estimate the strength of single integrin-fibrinogen pair at different loading rates. For loading rates of 10-60 nN/s, the debonding strength of a single integrin-fibrinogen pair was found to be in the range of 50-80 pN and was independent of the underlying substrate. Results suggest that once the active platelet binding epitope in fibrinogen becomes exposed by surface adsorption, binding of the platelet membrane integrin receptor will be similar regardless of the material surface properties.
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U2 - 10.1016/j.colsurfb.2009.01.019
DO - 10.1016/j.colsurfb.2009.01.019
M3 - Article
C2 - 19250806
AN - SCOPUS:64849110622
SN - 0927-7765
VL - 71
SP - 138
EP - 147
JO - Colloids and Surfaces B: Biointerfaces
JF - Colloids and Surfaces B: Biointerfaces
IS - 1
ER -