Silk-based Double-sided Magnetic Microneedles for Enhanced Targeted Retention in the Gastrointestinal Tract

This study reports the development of silk-based double-sided magnetic microneedles (SDMMs) for targeted oral drug delivery with magnetically enhanced gastrointestinal retention. The SDMMs integrate silk fibroin as a biodegradable structural material with iron oxide nanoparticles (IONPs) for magnetic responsiveness. The devices exhibit strong mechanical performance, site-specific degradation, and compatibility with capsule-based delivery systems. In vitro studies confirm region-dependent release kinetics and tunable degradation rates, while ex vivo and in vivo tests demonstrate superior gastric and intestinal retention—maintaining attachment under flow rates of 550 mL min⁻¹ (stomach) and 400 mL min⁻¹ (small intestine). Magnetic assistance extends GI retention to nearly 15 hours, significantly improving localized therapeutic delivery.