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Molecularly designed surfaces for blood deheparinization using an immobilized heparin‐binding peptide
Author(s) -
Martins M. Cristina L.,
Curtin Scott A.,
Freitas Sidónio C.,
Salgueiro Pedro,
Ratner Buddy D.,
Barbosa Mário A.
Publication year - 2009
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.31849
Subject(s) - heparin , materials science , adsorption , protamine , monolayer , nuclear chemistry , protein adsorption , fourier transform infrared spectroscopy , attenuated total reflection , polymer chemistry , infrared spectroscopy , chemistry , chemical engineering , organic chemistry , nanotechnology , biochemistry , engineering
Systemic heparinization, used during haemodialysis to prevent blood clotting on the extracorporeal circuit, leads to a high incidence of hemorrhagic complications. The adverse reactions associated with heparin neutralization using protamine sulphate justify the development of an alternative system for blood deheparinization. The main objective of this work is to design nanostructured surfaces with the capacity to bind heparin from blood in a selective way. A heparin‐binding polypeptide, composed of L ‐lysine and L ‐leucine (pKL), was synthesized and immobilized, in different concentrations, onto self‐assembled monolayers (SAMs) terminated with tetra(ethylene‐glycol) (EG4 SAMs). Immobilization was performed using a fixed concentration of pKL after surface activation to different degrees using a range of CDI ( N , N ′‐carbonyldiimidazole) concentrations. Results demonstrated that the presence of pKL increases heparin adsorption to EG4‐SAMs, independently of the pKL concentration and the way of immobilization (adsorption or covalent bound). Selectivity towards heparin was successfully achieved on SAMs with low concentrations of immobilized pKL (9–17% of pKL). Surfaces were characterized using ellipsometry, contact angle measurements, Fourier transform infrared reflection absorption spectroscopy (IRAS), atomic force microscopy, and X‐ray photoelectron spectroscopy. Heparin adsorption was assessed using IRAS and N ‐sulphonate‐ 35 S‐heparin. Therefore, this study could give a good contribution for the design of blood deheparinization devices. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009