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.