Highly Porous Silk Fibroin Scaffold Packed in PEGDA/Sucrose Microneedles for Controllable Transdermal Drug Delivery

Polymeric microneedles have attracted increasing attention as a minimally invasive platform for delivering drugs or vaccines in a more patient-friendly manner. However, traditional microfabrication techniques using negative molds with needle-shaped cavities usually require cumbersome centrifugation and vacuum degassing processes, which have restricted the scaled-up mass production of polymeric microneedles. Herein, a novel polydimethylsiloxane (PDMS)-based negative mold with cavities packed with silk fibroin scaffold is developed for rapid fabrication of polymeric microneedles, which comprise primarily the composition of poly(ethylene glycol) diacrylate (PEGDA) and sucrose as the needle matrix. Fibroin scaffolds can instantly adsorb prepolymer solution due to capillary force, and subsequently initiate the formation of microneedles via photoinduced polymerization. Based on three types of model drugs, including Rhodamine B (RhB), indocyanine green (ICG), and doxorubicin (DOX), the fabricated PEGDA/sucrose microneedles can realize effective transdermal delivery and controllable release of therapeutic molecules by regulating the sucrose content. The presented method provides a simple strategy for quick fabrication of polymeric microneedles toward transdermal drug delivery applications.