A Spatiotemporally Controllable Magnetic Microneedle for Targeted Gastric Drug Delivery

Abstract

Gastric-targeted drug delivery integrates oral convenience and local therapeutic action, aiming to improve precision while reducing systemic side effects. However, the extreme acidic environment, thick mucus and continuous peristalsis in the stomach are all the challenges resulting in inefficient or even ineffective gastric administration of drug. Here we report a spatiotemporally controllable ship-shaped magnetic microneedle featuring a magnetic base and an array of pH-responsive conical microcavity loaded drug powder for targeted gastric drug delivery. Benefiting from the magnetic and pH-responsive functions, the microneedle remains stable in gastric lumen, orients and penetrates into the mucosa under the magnetic field, and rapidly releases the drugs upon exposure to the near-neutral environment beneath the mucus barrier. Additionally, the design of conical microcavity enable the microneedle to carry versatile drugs, including small molecules and biomacromolecules. In canine models, the microneedle exhibited flexible responsiveness to an external magnetic field. When evaluated in rabbit models using fluorescent molecules and insulin as model drugs, the microneedles exhibited efficacy in prolonging fluorescence retention and regulating blood glucose, respectively, without obvious side effects. This ship-shaped magnetic microneedle promises new horizons for efficient gastric drug administration and precise therapy.