TY - JOUR
T1 - Unraveling the mechanism of nanotube formation by chiral self-assembly of amphiphiles
AU - Ziserman, Lior
AU - Lee, Hee Young
AU - Raghavan, Srinivasa R.
AU - Mor, Amram
AU - Danino, Dganit
PY - 2011/3/2
Y1 - 2011/3/2
N2 - The self-assembly of nanotubes from chiral amphiphiles and peptide mimics is still poorly understood. Here, we present the first complete path to nanotubes by chiral self-assembly studied with C12- β12 (N-α-lauryl-lysyl-aminolauryl-lysyl-amide), a molecule designed to have unique hybrid architecture. Using the technique of direct-imaging cryo-transmission electron microscopy (cryo-TEM), we show the time-evolution from micelles of C12-β12 to closed nanotubes, passing through several types of one-dimensional (1-D) intermediates such as elongated fibrils, twisted ribbons, and coiled helical ribbons. Scattering and diffraction techniques confirm that the fundamental unit is a monolayer lamella of C12-β12, with the hydrophobic tails in the gel state and β-sheet arrangement. The lamellae are held together by a combination of hydrophobic interactions, and two sets of hydrogen-bonding networks, supporting C12-β12 monomers assembly into fibrils and associating fibrils into ribbons. We further show that neither the "growing width" model nor the "closing pitch" model accurately describe the process of nanotube formation, and both ribbon width and pitch grow with maturation. Additionally, our data exclusively indicate that twisted ribbons are the precursors for coiled ribbons, and the latter structures give rise to nanotubes, and we show chirality is a key requirement for nanotube formation.
AB - The self-assembly of nanotubes from chiral amphiphiles and peptide mimics is still poorly understood. Here, we present the first complete path to nanotubes by chiral self-assembly studied with C12- β12 (N-α-lauryl-lysyl-aminolauryl-lysyl-amide), a molecule designed to have unique hybrid architecture. Using the technique of direct-imaging cryo-transmission electron microscopy (cryo-TEM), we show the time-evolution from micelles of C12-β12 to closed nanotubes, passing through several types of one-dimensional (1-D) intermediates such as elongated fibrils, twisted ribbons, and coiled helical ribbons. Scattering and diffraction techniques confirm that the fundamental unit is a monolayer lamella of C12-β12, with the hydrophobic tails in the gel state and β-sheet arrangement. The lamellae are held together by a combination of hydrophobic interactions, and two sets of hydrogen-bonding networks, supporting C12-β12 monomers assembly into fibrils and associating fibrils into ribbons. We further show that neither the "growing width" model nor the "closing pitch" model accurately describe the process of nanotube formation, and both ribbon width and pitch grow with maturation. Additionally, our data exclusively indicate that twisted ribbons are the precursors for coiled ribbons, and the latter structures give rise to nanotubes, and we show chirality is a key requirement for nanotube formation.
UR - http://www.scopus.com/inward/record.url?scp=79952265946&partnerID=8YFLogxK
U2 - 10.1021/ja107069f
DO - 10.1021/ja107069f
M3 - 文章
C2 - 21244023
AN - SCOPUS:79952265946
SN - 0002-7863
VL - 133
SP - 2511
EP - 2517
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 8
ER -