One dimensional (1D) organic nanotubes (ONTs) have emerged as an important class of nanostructures with high aspect ratios and large internal surface areas for applications in nanotechnology and medicine, including catalysis, optics, electronics, chemical or biological sensors, and tissue engineering. In the past decades, a wide range of single-walled and multi-walled ONTs have been synthesized through the assembly of amphiphilic small molecules or macromolecules. Despite all these advances in ONT development, integration of sequence-defined engineering and dynamic response characteristics into ONTs is a challenging task. In addition, despite the continuing emergence of new applications of ONTs, fundamentals, such as the mechanism of the formation of ONTs that is crucial to ONT properties and applications, are still the missing piece of the puzzle.
Here we report a new family of highly-designable, dynamic and stiff nanotubes assembled from sequence-defined peptoids through a unique “rolling-up and closure of nanosheet” mechanism. During the assembly process, amorphous spherical particles of amphiphilic peptoid oligomers crystallize to form well-defined nanosheets before folding to form single-walled nanotubes. These nanotubes undergo a pH-triggered, reversible contraction-expansion motion. By varying the number of hydrophobic residues of peptoids, we demonstrate the tuning of nanotube wall thickness, diameter, and mechanical properties. Atomic force microscopy based mechanical measurements show PNTs are highly stiff (Young’s Modulus ~13-17 GPa). We further demonstrate the precise incorporation of functional groups within peptoid nanotubes and their applications in water decontamination and cellular adhesion and uptake. These nanotubes provide a robust platform for developing biomimetic materials tailored to specific applications.
1. Jin, H. B.; Ding, Y.-H.; Wang, M.; Song, Y.; Liao, L.; Newcomb, C. J.; Wu, X.; Tang, X.-Q.; Li, Z.; Lin, Y.; Yan, F.; Jian, T.; Mu, P.; Chen, C. L. Designable and Dynamic Single-Walled Stiff Nanotubes Assembled from Sequenced-Defined Peptoids. Nature Commun. 2017, in press.