Light–induced disassembly of self-assembled vesicle-capped nanotubes observed in real time

Abstract

Molecular self-assembly is the basis for the formation of numerous artificial nanostructures. The self-organization of peptides, amphiphilic molecules composed of fused benzene rings and other functional molecules into nanotubes is of particular interest. However, the design of dynamic, complex self-organized systems that are responsive to external stimuli remains a significant challenge. Here, we report self-assembled, vesicle-capped nanotubes that can be selectively disassembled by irradiation. The walls of the nanotubes are 3-nm-thick bilayers and are made from amphiphilic molecules with two hydrophobic legs that interdigitate when the molecules self-assemble into bilayers. In the presence of phospholipids, a phase separation between the phospholipids and the amphiphilic molecules creates nanotubes, which are end-capped by vesicles that can be chemically altered or removed and reattached without affecting the nanotubes. The presence of a photoswitchable and fluorescent core in the amphiphilic molecules allows fast and highly controlled disassembly of the nanotubes on irradiation, and distinct disassembly processes can be observed in real time using fluorescence microscopy.

Transmission Electron Microscopy as a Tool for the Characterization of Soft Materials: Application and Interpretation

“…For their urge to build more complex systems, supramolecular chemistry,1 dynamic combinatorial chemistry2 and systems chemistry3 rely on high‐quality TEM data 4, 5. The chemistry has evolved from single molecules towards molecular systems in which functionality and responsiveness are integrated in nano‐structured materials,6 for which TEM is an essential and powerful tool.…”

“…This becomes apparent when, upon drying, similar structures appear sometimes black (high‐density material) and sometimes white (low‐density material) even within one figure. In this essay, each of the three approaches is demonstrated with doxorubicin‐loaded stealth liposomes17, 18 and amphiphilic nanotubes4, 19 and reviewed with respect to their possibilities and limitations for soft materials.…”

Artificial microtubules burst with energy

“…noncovalent interactions, and responsive nanotubes (12,13). For example, a self-assembled supramolecular polymer fiber was recently reported, which could contract and expand in a manner reminiscent of muscle fibers (14).…”

Self-assembly of artificial microtubules

“…11,14,15 Tubular structures are also found to form in self-assembly of macromolecules that are usually amphiphilic. 2,[16][17][18][19][20][21][22][23][24][25][26] The location of hydrophobic and hydrophilic groups and other non-covalent interaction sites results in the formation of tubes. The key issue is to understand what features (shapes, chirality, binding strengths, etc.)…”