Premium
Selective protein adsorption modulates platelet adhesion and activation to oligo(ethylene glycol)‐terminated self‐assembled monolayers with C18 ligands
Author(s) -
Gonçalves Inês C.,
Martins M. Cristina L.,
Barbosa Mário A.,
Naeemi Esmaeel,
Ratner Buddy D.
Publication year - 2008
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.32011
Subject(s) - human serum albumin , ethylene glycol , contact angle , protein adsorption , monolayer , materials science , adhesion , glutaraldehyde , self assembled monolayer , platelet activation , x ray photoelectron spectroscopy , adsorption , biophysics , platelet , nuclear chemistry , chemical engineering , chemistry , biochemistry , organic chemistry , nanotechnology , biology , engineering , immunology , composite material
This study focuses on the selective binding of albumin to a nanostructured surfaces to inhibit other blood proteins from adsorbing thereby reducing platelet adhesion and activation. Tetra (ethylene‐glycol)‐terminated self‐assembled monolayers (EG4 SAMs) with different percentages of C18 ligands on the surface were characterized by contact angle measurements, X‐ray photoelectron microscopy, infrared reflection‐absorption spectroscopy, and ellipsometry. A specific surface (2.5% C18 SAM) was found to be selective for human serum albumin (HSA) in the presence of both albumin and fibrinogen (HFG). The importance of this concentration of C18 ligands was stressed in reversibility studies since that surface exchanged almost all the preadsorbed HSA by HSA in solution, but not by HFG. The effect of protein adsorption in the subsequent adhesion and activation of platelets was studied by pre‐immersing the surfaces in albumin and plasma before contact with platelets. Scanning electron microscopy and glutaraldehyde induced fluorescence technique images showed that as surfaces got more hydrophobic due to the immobilization of C18 ligands, the number of adherent platelets increased and their morphology changed from round to fully spread. Pre‐immersion in HSA led to an 80% decrease in platelet adhesion and reduction of activation. Pre‐immersion in 1% plasma was only relevant in 2.5% C18 SAMs since this was the only surface that demonstrated less adhesion of platelets comparing with buffer pre‐immersion. However, they still adsorb more platelets then when HSA was preadsorbed. This was confirmed in competition studies between HSA and plasma that suggested that other plasma proteins were also adsorbing to this surface. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009