Preparation and Characterization of Ionic Conductive Poly(acrylic Acid)-Based Silicone Hydrogels for Smart Drug Delivery System

In this study, we developed a smart drug delivery system that can efficiently deliver the required amounts of drugs using the excellent ion conductivity of poly(acrylic acid) (PAA) and an electrical stimulus. As a result of its having carboxyl groups, PAA hydrogel can be used in drug delivery patches to release drugs by ionic conductivity. However, PAA hydrogel has low durability and poor mechanical properties. The carboxyl group of PAA was combined with a siloxane group of silicone using electron-beam irradiation to easily form a crosslinked structure. The PAA–silicone hydrogel has excellent mechanical properties. Specifically, the tensile strength increased more than 3.5 times. In addition, we observed its cell compatibility using fluorescence staining and CCK-8 assays and found good cell viability. Finally, it was possible to control the drug delivery rate efficiently using the voltage applied to the ion-conductive hydrogel. As the voltage was increased to 3, 5, and 7 V, the amount of drug released was 53, 88, and 96%, respectively. These excellent properties of the PAA–silicone hydrogel can be used not only for whitening or anti-wrinkling cosmetics but also in medical drug-delivery systems.