Force-controlled release of small molecules with a rotaxane actuator

Area of Science:

• Supramolecular Chemistry
• Polymer Mechanochemistry
• Materials Science

Background:

• Force-controlled release of small molecules is crucial for drug delivery and agent release.
• Existing polymer mechanochemistry methods face limitations in cargo diversity and quantity released per event.
• Previous systems struggle with iterative activation and non-specific release issues.

Purpose of the Study:

• To develop a novel molecular actuator for efficient, force-controlled release of multiple cargo molecules.
• To demonstrate the versatility of a rotaxane-based system for diverse release applications.
• To overcome the limitations of existing mechanochemical release systems.

Main Methods:

• Utilized a rotaxane molecule as a molecular actuator.
• Appended cargo molecules to the rotaxane axle for controlled release.
• Triggered release through mechanical force (ultrasonication and compression).

Main Results:

• Achieved release of up to five cargo molecules per rotaxane actuator.
• Demonstrated high release efficiencies (up to 71% in solution, 30% in bulk).
• Successfully released representative functional molecules: a drug, fluorescent tag, and organocatalyst.

Conclusions:

• Rotaxane actuators offer a highly efficient and versatile platform for force-controlled molecular release.
• This system overcomes previous limitations in cargo loading and release efficiency.
• Presents a promising approach for advanced drug delivery and materials science applications.