title: Rational Design of Multilayer Collagen Nanosheets with Compositional and Structural Control.
abstract: Two collagen-mimetic peptides, CP(+) and CP(-), are reported in which the sequences comprise a multiblock architecture having positively charged N-terminal (Pro-Arg-Gly)3 and negatively charged C-terminal (Glu-Hyp-Gly)3 triad extensions, respectively. CP(+) rapidly self-associates into positively charged nanosheets based on a monolayer structure. In contrast, CP(-) self-assembles to form negatively charged monolayer nanosheets at a much slower rate, which can be accelerated in the presence of calcium(II) ion. A 2:1 mixture of unassociated CP(-) peptide with preformed CP(+) nanosheets generates structurally defined triple-layer nanosheets in which two CP(-) monolayers have formed on the identical surfaces of the CP(+) nanosheet template. Experimental data from electrostatic force microscopy (EFM) image analysis, zeta potential measurements, and charged nanoparticle binding assays support a negative surface charge state for the triple-layer nanosheets, which is the reverse of the positive surface charge state observed for the CP(+) monolayer nanosheets. The electrostatic complementarity between the CP(+) and CP(-) triple helical cohesive ends at the layer interfaces promotes a (CP(-)/CP(+)/CP(-)) compositional gradient along the z-direction of the nanosheet. This structurally informed approach represents an attractive strategy for the fabrication of two-dimensional nanostructures with compositional control.
authors.affiliation: †Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
authors.affiliation: ‡School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
authors.forename: Owen A
authors.initials: OA
authors.lastname: Vail
authors.affiliation: ‡School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: §X-ray Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Zuo
authors.affiliation: †Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.
authors.forename: Vincent P
authors.initials: VP
authors.lastname: Conticello
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D003094:Collagen / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D055672:Static Electricity
chemical_list: D010455:Peptides; D003094:Collagen