Degradation-Induced Actuation in Oxidation-Responsive Liquid Crystal Elastomers.

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomedical Engineering

Background:

• Stimuli-responsive materials are crucial for advanced implantable medical devices.
• Liquid crystal elastomers (LCEs) offer tunable mechanical properties and shape-memory effects.
• Designing materials that respond to specific biological conditions, like reactive oxygen species, is a key challenge.

Purpose of the Study:

• To synthesize and characterize novel oxidation-responsive LCEs.
• To investigate the programmable shape-changing capabilities of these LCEs in response to reactive oxygen species.
• To evaluate the degradation behavior of LCEs in various physiological conditions.

Main Methods:

• Synthesis of oxidation-sensitive LCEs.
• Fabrication of LCE structures using direct ink writing (DIW) for controlled molecular orientation.
• In vitro testing of LCEs in oxidative, basic, and saline media at body temperature.

Main Results:

• LCEs exhibited significant anisotropic shape changes (8% contraction, 16% expansion) in oxidative media due to thioether to sulfoxide/sulfone conversion.
• 3D-printed LCEs deformed into cones with 19x increased thickness.
• LCEs degraded completely in oxidative conditions but remained stable in basic and saline solutions.

Conclusions:

• Oxidation-responsive LCEs demonstrate programmable shape changes triggered by reactive oxygen species.
• The observed anisotropic swelling and degradation offer potential for targeted drug delivery and diagnostic tools.
• These LCEs show promise for developing next-generation responsive implantable medical devices.