title: Sequential and competitive adsorption of peptides at pendant PEO layers.
abstract: Earlier work provided direction for development of responsive drug delivery systems based on modulation of the structure, amphiphilicity, and surface density of bioactive peptides entrapped within pendant polyethylene oxide (PEO) brush layers. In this work, we describe the sequential and competitive adsorption behavior of such peptides at pendant PEO layers. Three cationic peptides were used for this purpose: the arginine-rich, amphiphilic peptide WLBU2, a peptide chemically identical to WLBU2 but of scrambled sequence (S-WLBU2), and the non-amphiphilic peptide poly-L-arginine (PLR). Optical waveguide lightmode spectroscopy (OWLS) was used to quantify the rate and extent of peptide adsorption and elution at surfaces coated with PEO. UV spectroscopy and time-of-flight secondary ion mass spectrometry (TOF-SIMS) were used to quantify the extent of peptide exchange during the course of sequential and competitive adsorption. Circular dichroism (CD) was used to evaluate conformational changes after adsorption of peptide mixtures at PEO-coated silica nanoparticles. Results indicated that amphiphilic peptides are able to displace adsorbed, non-amphiphilic peptides in PEO layers, while non-amphiphilic peptides were not able to displace more amphiphilic peptides. In addition, peptides of greater amphiphilicity dominated the adsorption at the PEO layer from mixtures with less amphiphilic or non-amphiphilic peptides.
authors.affiliation: Agere Pharmaceuticals, Bend, OR 97701, USA.
authors.forename: Xiangming
authors.initials: X
authors.lastname: Wu
authors.affiliation: School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Ryder
authors.affiliation: School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: McGuire
authors.affiliation: Grace Bio-Labs, Bend, OR 97702, USA.
authors.forename: Joshua L
authors.initials: JL
authors.lastname: Snider
authors.affiliation: School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA. Electronic address: karl.schilke@oregonstate.edu.
authors.forename: Karl F
authors.initials: KF
authors.lastname: Schilke
mesh_terms: D000327:Adsorption; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000378:metabolism; D001120:Arginine / Q000737:chemistry*; D001667:Binding, Competitive; D002942:Circular Dichroism; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D013058:Mass Spectrometry / Q000379:methods; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet; D013499:Surface Properties
chemical_list: D023181:Antimicrobial Cationic Peptides; D010455:Peptides; C520840:WLBU2 peptide; C015462:polyarginine; D011092:Polyethylene Glycols; D001120:Arginine
keywords: Cationic amphiphilic peptides; Competitive adsorption; PEO brush; Polyarginine; Sequential adsorption; WLBU2