From the early stages of contact with the biological environment, the material surfaces are covered by a “corona” of endogenous proteins. Understanding of the subsequent cells response, therefore, is the study of the new “epitopes”, formed by material surface termination and amount/orientation of adsorbed proteins. Nanosized hydroxyapatite particles (HA), are among materials of interest as biomimetic counterpart of inorganic phase of bones and teeth. The HA lattice can be described as sequence of Ca3(PO4)2 (A) and Ca4(PO4)2(OH)2 (B) layers parallel to 010 crystal planes. Depending on their sequence (A-B-A, A-A-B or B-A-A), they give rise to stoichiometric HA(010) and nonstoichiometric HA(010)_Ca-rich and HA(010)_P-rich surfaces, respectively, having different preferential adsorption of acidic and basic proteins. The use of a theoretical-experimental model based on IR of CO adsorbed as probe molecule allowed to establish that two types of HA nanoparticles exposedCa-rich and P-rich surfaces.The two materials exhibited ζ-potentials different in value and sign when suspended in HEPES buffer. Moreover an inverse trend of ζ-potentials is observed once a monolayer of adsorbed BSA was attained by incubation in a buffered BSA solution (surface coverage also monitored by effects on CD-UV spectraof adsorbed BSA). Since a complete protein coverage prevents the contribution of HA surfaces to the ζ-potential, these should therefore stem from differences in “surfaces” exposed to the liquid medium by adsorbed proteins oriented in different ways on the two HA.
Proteins adsorbed on hydroxyapatite nanoparticles; factors determining a material new biological identity
CATALANO, FEDERICO;IVANCHENKO, PAVLO;SAKHNO, YURIY;AINA, VALENTINA;MARTRA, Gianmario
2014-01-01
Abstract
From the early stages of contact with the biological environment, the material surfaces are covered by a “corona” of endogenous proteins. Understanding of the subsequent cells response, therefore, is the study of the new “epitopes”, formed by material surface termination and amount/orientation of adsorbed proteins. Nanosized hydroxyapatite particles (HA), are among materials of interest as biomimetic counterpart of inorganic phase of bones and teeth. The HA lattice can be described as sequence of Ca3(PO4)2 (A) and Ca4(PO4)2(OH)2 (B) layers parallel to 010 crystal planes. Depending on their sequence (A-B-A, A-A-B or B-A-A), they give rise to stoichiometric HA(010) and nonstoichiometric HA(010)_Ca-rich and HA(010)_P-rich surfaces, respectively, having different preferential adsorption of acidic and basic proteins. The use of a theoretical-experimental model based on IR of CO adsorbed as probe molecule allowed to establish that two types of HA nanoparticles exposedCa-rich and P-rich surfaces.The two materials exhibited ζ-potentials different in value and sign when suspended in HEPES buffer. Moreover an inverse trend of ζ-potentials is observed once a monolayer of adsorbed BSA was attained by incubation in a buffered BSA solution (surface coverage also monitored by effects on CD-UV spectraof adsorbed BSA). Since a complete protein coverage prevents the contribution of HA surfaces to the ζ-potential, these should therefore stem from differences in “surfaces” exposed to the liquid medium by adsorbed proteins oriented in different ways on the two HA.File | Dimensione | Formato | |
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