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Adsorption of charged albumin subdomains on a graphite surface
Author(s) -
Raffaini Giuseppina,
Ganazzoli Fabio
Publication year - 2005
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.30546
Subject(s) - materials science , adsorption , graphite , albumin , surface (topology) , surface modification , chemical engineering , composite material , organic chemistry , geometry , biochemistry , chemistry , engineering , mathematics
We report some new molecular dynamics simulation results about the adsorption on a hydrophobic graphite surface of two albumin subdomains, each formed by three different α‐helices, considering the correctly charged side groups at pH = 7 instead of the neutral ones as done in our previous exploratory paper (Raffaini and Ganazzoli, Langmuir 2003;19:3403–3412). We find that the presence of charges affects somewhat the initial adsorption stage on the electrostatically neutral surface, but not the final one. Thus, we recover the result that a monolayer of aminoacids is eventually formed, with a rough parallelism of distant strands to optimize both the intramolecular and the surface interactions. This feature is consistent with the adsorption on the hydrophobic surface being driven by dispersion forces only, and with the “soft” nature of albumin. Additional optimizations of the final monolayer carried out at pH = 3 and 11 do not modify appreciably this picture, suggesting that adsorption on graphite is basically independent of pH. The enhanced hydration of the final adsorption state due to the (delocalized) charges of the side groups is also discussed in comparison with similar results of the neutralized subdomains. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006