Concentration effects on peptide elution from pendant PEO layers.
In earlier work, we have provided direction for development of responsive drug delivery systems based on modulation of structure and amphiphilicity of bioactive peptides entrapped within pendant polyethylene oxide (PEO) brush layers. Amphiphilicity promotes retention of the peptides within the hydrophobic inner region of the PEO brush layer. In this work, we describe the effects of peptide surface density on the conformational changes caused by peptide-peptide interactions, and show that this phenomenon substantially affects the rate and extent of peptide elution from PEO brush layers. Three cationic peptides were used in this study: the arginine-rich amphiphilic peptide WLBU2, the chemically identical but scrambled peptide S-WLBU2, and the non-amphiphilic homopolymer poly-l-arginine (PLR). Circular dichroism (CD) was used to evaluate surface density effects on the structure of these peptides at uncoated (hydrophobic) and PEO-coated silica nanoparticles. UV spectroscopy and a quartz crystal microbalance with dissipation monitoring (QCM-D) were used to quantify changes in the extent of peptide elution caused by those conformational changes. For amphiphilic peptides at sufficiently high surface density, peptide-peptide interactions result in conformational changes which compromise their resistance to elution. In contrast, elution of a non-amphiphilic peptide is substantially independent of its surface density, presumably due to the absence of peptide-peptide interactions. The results presented here provide a strategy to control the rate and extent of release of bioactive peptides from PEO layers, based on modulation of their amphiphilicity and surface density.
School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA.
Xiangming
X
Wu
School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA.
Matthew P
MP
Ryder
School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA.
Joseph
J
McGuire
School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA. Electronic address: karl.schilke@oregonstate.edu.
Karl F
KF
Schilke
D000327:Adsorption; D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000302:isolation & purification*; D002942:Circular Dichroism; D008969:Molecular Sequence Data; D053758:Nanoparticles / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D017433:Protein Structure, Secondary; D058525:Quartz Crystal Microbalance Techniques; D013499:Surface Properties
D023181:Antimicrobial Cationic Peptides; D010455:Peptides; C520840:WLBU2 peptide; C015462:polyarginine; D011092:Polyethylene Glycols
Cationic amphiphilic peptides; Circular dichroism (CD); Coiled-coils; PEO brush; Peptide elution; Polyarginine; WLBU2; α-Helix