Main content area

Rational Design of Multilayer Collagen Nanosheets with Compositional and Structural Control

Jiang, Tao, Vail, Owen A., Jiang, Zhigang, Zuo, Xiaobing, Conticello, Vincent P.
Journal of the American Chemical Society 2015 v.137 no.24 pp. 7793-7802
calcium, collagen, electrostatic interactions, image analysis, microscopy, nanoparticles, nanosheets, peptides, zeta potential
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.