Effect of peptide secondary structure on adsorption and adsorbed film properties on end-grafted polyethylene oxide layers

  1. Get@NRC: Effect of peptide secondary structure on adsorption and adsorbed film properties on end-grafted polyethylene oxide layers (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1016/j.actbio.2013.09.010
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Journal titleActa Biomaterialia
Pages5666; # of pages: 11
Subjectbiomaterial; gold; macrogol; peptide; polylysine; protein; solvent; water; adsorption; article; circular dichroism; film; material coating; peptide analysis; priority journal; protein adsorption; protein secondary structure; quartz crystal microbalance; sensor; thickness; viscosity
AbstractPoly-l-lysine (PLL), in α-helix or β-sheet configuration, was used as a model peptide for investigating the effect of secondary structures on adsorption events to poly(ethylene oxide) (PEO) modified surfaces formed using θ solvents. Circular dichroism results showed that the secondary structure of PLL persisted upon adsorption to Au and PEO modified Au surfaces. Quartz crystal microbalance with dissipation (QCM-D) was used to characterize the chemisorbed PEO layer in different solvents (θ and good solvents), as well as the sequential adsorption of PLL in different secondary structures (α-helix or β-sheet). QCM-D results suggest that chemisorption of PEO 750 and 2000 from θ solutions led to brushes 3.8 ± 0.1 and 4.5 ± 0.1 nm thick with layer viscosities of 9.2 ± 0.8 and 4.8 ± 0.5 cP, respectively. The average number of H2O per ethylene oxides, while in θ solvent, was determined as ∼0.9 and ∼1.2 for the PEO 750 and 2000 layers, respectively. Upon immersion in good solvent (as used for PLL adsorption experiments), the number of H2O per ethylene oxides increased to ∼1.5 and ∼2.0 for PEO 750 and 2000 films, respectively. PLL adsorbed masses for α-helix and β-sheet on Au sensors was 231 ± 5 and 1087 ± 14 ng cm-2, with layer viscosities of 2.3 ± 0.1 and 1.2 ± 0.1 cP, respectively; suggesting that the α-helix layer was more rigid, despite a smaller adsorbed mass, than that of β-sheet layers. The PEO 750 layer reduced PLL adsorbed amounts to ∼10 and 12% of that on Au for α-helices and β-sheets respectively. The PLL adsorbed mass to PEO 2000 layers dropped to ∼12% and 4% of that on Au, for α-helix and β-sheet respectively. No significant differences existed for the viscosities of adsorbed α-helix and β-sheet PLL on PEO surfaces. These results provide new insights into the fundamental understanding of the effects of secondary structures of peptides and proteins on their surface adsorption. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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AffiliationNational Research Council Canada (NRC-CNRC)
Peer reviewedYes
NPARC number21270771
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Record identifier45243360-0bc7-43df-b33f-d438ce346704
Record created2014-02-17
Record modified2016-05-09
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