Digital Light Processing of Methacrylated Silk Fibroin Microneedles: Precision Engineering for Enhanced Transdermal Delivery and Skin Regeneration

Despite the promising potential of digital light processing (DLP)─fabricated silk fibroin (SF) microneedles (MNs) in transdermal applications, their clinical translation faces two major challenges: insufficient manufacturing precision to achieve architectural resolution and inadequate mechanical strength to penetrate the epidermis effectively. To overcome these critical barriers, we developed a methacrylated silk fibroin (Sil-MA) bioink that combines high biocompatibility with enhanced printability. By systematically optimizing material formulation, printing parameters and MN geometry, we successfully fabricated DLP-printed Sil-MA MNs with precise architecture control and superior mechanical performance. These MNs demonstrated no cytotoxicity and enabled efficient transdermal delivery of three distinct dermatological therapeutics. Comprehensive in vitro and in vivo assessments indicated that the DLP-printed Sil-MA MNs also acted as mechanical stimulators, significantly promoting epidermal keratinocyte proliferation. This engineered platform offers a versatile strategy for developing multifunctional MN systems for therapeutic delivery and tissue engineering applications.