Electrically Responsive Microneedles based on Polypyrrole?Silk Fibroin Composite Hydrogels

초록

Microneedle (MN) is a non-invasive, painless drug administration method. Hydrogel forming microneedle (HFM) can encapsulate a high concentration of various molecules in its polymeric network and easily release drugs by swelling behavior under physiological conditions. Although it has excellent encapsulation efficiency, the weak mechanical strength of the hydrogel and the hydration-induced uncontrollable burst release of molecules are limitations of the HFM system. Silk fibroin (SF) is a robust, biocompatible natural polymer that can achieve sufficient mechanical strength for microneedles. Polypyrrole (PPy) is an electrically conductive polymer that can induce network changes in the hydrogel structure. In this study, a PPy incorporated SF hydrogel-based stimuli-responsive drug-releasing microneedle system was demonstrated. Above 0.1 N/needle of penetration force was achieved, and the ex vivo release property of SF@PPy MN was verified. These results indicate SF-based HFM may penetrate the skin or tissues successfully. Additionally, the controlled drug release property of hydrogels can be applied to various applications in tissue engineering, such as implantable hydrogels, 3D tissue-regenerating scaffolds, and on-demand drug administration platforms. This study proposes an electrical-stimulus-based sustainable drug-releasing microneedle that can be a method for various applications in biopharmaceuticals like diabetes, ocular drug delivery, and hormone delivery._