Microgel-Based Stretchable Reservoir Devices for Elongation Enhanced Small Molecule Release Rate

Area of Science:

• Materials Science
• Biomedical Engineering
• Drug Delivery Systems

Background:

• Developing controlled drug release systems is crucial for effective therapeutics.
• Microgel-based devices offer tunable properties for drug encapsulation and release.
• Controlling release kinetics through external stimuli like mechanical stress is an active research area.

Purpose of the Study:

• To fabricate stretchable microgel reservoir devices for controlled release of crystal violet (CV).
• To investigate the influence of gold (Au) layer thickness and device elongation on CV release rates.
• To explore the potential for autonomous drug release systems triggered by natural movements.

Main Methods:

• Fabrication of stretchable poly(N-isopropylacrylamide)-co-acrylic acid (pNIPAm-co-10% AAc) microgel reservoir devices.
• Loading of crystal violet (CV) into microgels via electrostatic interactions at pH 6.5.
• Triggering CV release by changing solution pH to 3.0 and analyzing release kinetics under varying Au layer thickness and device elongation.

Main Results:

• CV release was triggered by a pH shift, breaking electrostatic interactions.
• Decreasing Au layer thickness and increasing device elongation accelerated CV release.
• Au layer thickness dominated release at low elongation, while elongation-induced cracks dominated at high elongation, enabling an 'off' to 'on' release transition.

Conclusions:

• Stretchable microgel devices with tunable Au coatings and mechanical properties can precisely control drug release kinetics.
• The interplay between Au layer porosity and elongation-induced cracking offers a mechanism for modulating release rates.
• These findings support the development of autonomous drug delivery systems activated by mechanical stimuli.