pH-Triggered Release from Polyamide Microcapsules Prepared by Interfacial Polymerization of a Simple Diester Monomer

Area of Science:

• Materials Science
• Polymer Chemistry
• Drug Delivery Systems

Background:

• Current pH-triggered release systems often respond to only low or high pH.
• Polyampholyte-based encapsulants have limited cargo capacity and retention.
• A need exists for versatile microcapsules with tunable release profiles.

Purpose of the Study:

• To develop high-capacity microcapsules with tunable dual pH-triggered release.
• To engineer polyamide microcapsules stable in nonpolar environments but responsive to pH changes.
• To investigate the effect of cross-linking on release kinetics.

Main Methods:

• Utilized interfacial polymerization between polyamines and pyromellitic diester diacid chloride.
• Fabricated "liquid core-shell" polyamide microcapsules.
• Investigated release profiles at pH 5, 7.4, and 10.
• Adjusted amine cross-linker feed ratio to tune cross-linking density.

Main Results:

• Achieved high-capacity polyamide microcapsules with tunable dual acid/base-triggered release.
• Demonstrated steady release at pH 7.4 and accelerated release at pH 5 and 10.
• Showcased tunable release rates by varying the cross-linker feed ratio.
• Confirmed suitable barrier properties and stability in dry/nonpolar conditions.

Conclusions:

• Developed novel polyamide microcapsules with tunable dual pH-triggered release capabilities.
• These microcapsules offer improved loading capacity and cargo retention compared to polyampholytes.
• The tunable release mechanism enables applications across a wide range of pH environments.