Photoreconfigurable supramolecular nanotube

Area of Science:

• Biomaterials Science
• Supramolecular Chemistry
• Nanotechnology

Background:

• Chaperonin proteins like GroEL can self-assemble into higher-order structures.
• Photochromic molecules can switch between states upon light exposure, enabling dynamic control.
• Supramolecular polymerization offers a route to construct ordered nanomaterials.

Purpose of the Study:

• To develop a photoreconfigurable bionanotube using a modified chaperonin protein.
• To investigate the light-induced polymerization and depolymerization mechanisms.
• To explore the structural integrity and memory effects in the bionanotubes.

Main Methods:

• Engineered GroELSP protein with photochromic spiropyran (SP) units.
• Magnesium(II) ion-induced supramolecular polymerization.
• UV and visible light irradiation for photoisomerization and reconfiguration.
• Förster resonance energy transfer (FRET) for studying structural integrity.

Main Results:

• GroELSP polymerized into stable nanotubes (NTs) via Mg(2+)-mediated spiropyran (SP) to merocyanine (MC) isomerization.
• Visible light induced depolymerization (MC to SP), breaking NTs into smaller structures.
• Reversible reconfiguration of long NTs was achieved by alternating UV and visible light exposure.
• Sequential memory of NTs was lost upon successive visible and UV light exposure due to intertubular reshuffling.

Conclusions:

• A novel photoreconfigurable bionanotube system was successfully developed.
• The bionanotubes exhibit light-controllable assembly and disassembly.
• The study demonstrates the potential for dynamic control over nanomaterial structure and introduces light-induced memory loss mechanisms.