| Autor: |
Jiang T; †Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States., Vail OA; ‡School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States., Jiang Z; ‡School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States., Zuo X; §X-ray Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States., Conticello VP; †Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States. |
| Abstrakt: |
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. |
