Multi-stimuli responsive nanomaterials assembled from spiropyran-containing peptoids

Area of Science:

• Supramolecular chemistry
• Materials science
• Biomimetic catalysis

Background:

• Stimuli-responsive materials are crucial for tunable functionalities.
• Controlling supramolecular assembly morphology and crystallinity is key.
• Spiropyran (SP) photoisomerization offers a route to stimuli-responsive systems.

Purpose of the Study:

• To develop stimuli-responsive peptoid assemblies with tunable morphology and crystallinity.
• To investigate the role of spiropyran isomerization in assembly formation.
• To explore the application of these assemblies in mimicking enzyme catalysis.

Main Methods:

• Synthesis of amphiphilic peptoids incorporating a multifunctional spiropyran (SP) group.
• Characterization of self-assembled nanostructures (2D nanosheets, 1D nanotubes) using light and heat stimuli.
• Computational analysis using periodic density functional theory (DFT) to study SP/merocyanine (MC) energetics.
• Evaluation of catalytic activity in mimicking carbonic anhydrase (CA) enzymes.

Main Results:

• Amphiphilic peptoids self-assembled into light- and heat-responsive 2D nanosheets and 1D nanotubes.
• Spiropyran (SP) isomerization to merocyanine (MC) was confirmed as the mechanism for assembly control.
• DFT calculations showed MC dimers have more favorable packing energetics than SP dimers, correlating with higher assembly crystallinity.
• Catalytic activity, mimicking carbonic anhydrase, was tuned by controlling the assembly crystallinity.

Conclusions:

• Light and heat stimuli can effectively control the self-assembly of spiropyran-functionalized peptoids.
• The isomerization of spiropyran to merocyanine influences the packing and crystallinity of the assemblies.
• Tunable supramolecular assemblies offer a platform for developing responsive catalytic systems.