Tumbler-Inspired Oral Microrobot System with Dual Modules for On-Demand Gastric Drug Delivery.

Oral administration is the most common and patient friendly route for drug delivery. However, the harsh gastric environment severely compromises the stability and absorption of many therapeutics, particularly macromolecules. Here, we report an oral microrobot (OMR), inspired by a tumbler toy, designed for safe and efficient gastric drug delivery. The OMR incorporates interchangeable modules for either liquid drug injection or delivery of poorly soluble drugs via microneedles. Natural polysaccharides enhance adhesion to the gastric mucosa, dissolvable threads activate a spring-driven injection mechanism, and effervescent tablets enable controlled device detachment. In vivo studies in beagle dogs showed that, after oral administration, the protective shell dissolved under gastric conditions, triggering drug release. The macromolecular substance insulin, with its direct regulatory effect on blood glucose levels, has been selected as a typical model drug. Insulin delivered by the OMR injection module achieved a hypoglycemic effect comparable to subcutaneous injection. The OMR was excreted intact within 12 h without causing gastrointestinal injury. These findings demonstrate the potential of OMR system as a robust platform for delivering biologics otherwise inactivated in the gastrointestinal tract.