Active targeted therapy for bowel cancer using untethered microrobots has attracted extensive attention. However, traditional microrobots face challenges, such as issues of mobility, biocompatibility, drug loading, sustained-release capabilities, and targeting accuracy. Here, we propose an untethered triple-configurational magnetic robot (TCMR) that is composed of three geometrically nested parts: actuation and guarding, anchoring and seeding, and drug release part. A targeting magnetic driving system actuates the TCMR along the predetermined trajectory to the target position. The pH-sensitive actuation and guarding part formed by electrodeposition is degraded in the intestinal environment and separates from the two other parts. A majority of magnetic nanoparticles encapsulated in this part are retrieved. The anchoring and seeding part anchors the lesion area and seeds the drug release part in the gaps of intestinal villi by hydrolysis. Ultimately, the drug release part containing the therapeutic completes the sustained release to prolong the duration of the therapeutic agent. Cytotoxicity and therapeutic tests reveal that TCMRs are biocompatible and suitable for targeted therapy and have good therapeutic performance. The newly designed TCMR will provide new ideas for targeted therapy, thus expanding the application scope of robotics technology in the biomedical field.
Keywords: drug-sustained release; magnetic nanoparticles retrieval; targeted drug delivery; targeting magnetic driving system; triple-configurational magnetic robot.