MOF-based magnetic microrobot swarms for pH-responsive targeted drug delivery

Metal-organic frameworks(MOFs) hold significant potential as vehicles for drug delivery due to their expansive specific surface area, biocompatibility, and versatile attributes. Concurrently, magnetically actuated micro/nano-robots(MNRs) offer distinct advantages, such as untethered and precise manipulation. The fusion of these technologies presents a promising avenue for achieving non-invasive targeted drug delivery. Here, we report a MOF-based magnetic microrobot swarm(MMRS) for targeted therapy. Our approach overcomes limitations associated with a single MNR, including limited drug loading and the risk of loss during manipulation. We select Zeolitic Imidazolate Framework-8(ZIF-8) as the drug vehicle for its superior loading potential and p H-sensitive decomposition. Our design incorporates magnetic responsive components into the one-pot synthesis of Fe@ZIF-8, enabling collective behaviors under actuation. Tuning the yaw angle of alternating magnetic fields and nanoparticles’ amount, the MMRSs with controllable size achieve instantaneous transformation among different configurations, including vortex-like swarms, chain-like swarms, and elliptical swarms, facilitating adaptation to environmental variations. Transported to the subcutaneous T24 tumor site, the MMRSs with encapsulated doxorubicin(DOX) automatically degrade and release the drug,leading to a dramatic reduction of the tumor in vivo. Our investigation signifies a significant advancement in the integration of biodegradable MOFs into microrobot swarms, ushering in new avenues for accurate and non-invasive targeted drug delivery.