Magnetic-Acoustic Sequentially Actuated CAR T Cell Microrobots for Precision Navigation and In Situ Antitumor Immunoactivation.

Despite its clinical success, chimeric antigen receptor T (CAR T)-cell immunotherapy remains limited in solid tumors, owing to the harsh physical barriers and immunosuppressive microenvironment. Here a CAR-T-cell-based live microrobot (M-CAR T) is created by decorating CAR T with immunomagnetic beads using click conjugation. M-CAR Ts are capable of magnetic-acoustic actuation for precision targeting and in situ activation of antitumor immune responses. Sequential actuation endows M-CAR Ts with magnetically actuated anti-flow and obstacle avoidance as well as tissue penetration driven by acoustic propulsion, enabling efficient migration and accumulation in artificial tumor models. In vivo, sequentially actuated M-CAR Ts achieves long-distance targeting and accumulate at the peritumoural area under programmable magnetic guidance, and subsequently acoustic tweezers actuate M-CAR Ts to migrate into deep tumor tissues, resulting in a 6.6-fold increase in accumulated exogenous CD8+ CAR T cells compared with that without actuation. Anti-CD3/CD28 immunomagnetic beads stimulate infiltrated CAR T proliferation and activation in situ, significantly enhancing their antitumor efficacy. Thus, this sequential-actuation-guided cell microrobot combines the merits of autonomous targeting and penetration of intelligent robots with in situ T-cell immunoactivation, and holds considerable promise for precision navigation and cancer immunotherapies.

Multimodal Locomotion and Cargo Transportation of Magnetically Actuated Quadruped Soft Microrobots.

Untethered microrobots have attracted extensive attention due to their potential for biomedical applications and micromanipulation at the small scale. Soft microrobots are of great research importance because of their highly deformable ability to achieve not only multiple locomotion mechanisms but also minimal invasion to the environment. However, the existing microrobots are still limited in their ability to locomote and cross obstacles in unstructured environments compared to conventional legged robots. Nature provides much inspiration for developing miniature robots. Here, we propose a bionic quadruped soft thin-film microrobot with a nonmagnetic soft body and 4 magnetic flexible legs. The quadruped soft microrobot can achieve multiple controllable locomotion modes in the external magnetic field. The experiment demonstrated the robot's excellent obstacle-crossing ability by walking on the surface with steps and moving in the bottom of a stomach model with gullies. In particular, by controlling the conical angle of the external conical magnetic field, microbeads gripping, transportation, and release of the microrobot were demonstrated. In the future, the quadruped microrobot with excellent obstacle-crossing and gripping capabilities will be relevant for biomedical applications and micromanipulation.

A magnetically controlled soft miniature robotic fish with a flexible skeleton inspired by zebrafish.

The untethered miniature swimming robot actuation and control is difficult as the robot size becomes smaller, due to limitations of feasible miniaturized on-board components. Nature provides much inspiration for developing miniature robot. Here, a new artificial untethered miniature robotic fish with a flexible magnetic skeleton and soft body that achieve controlled locomotion under the water through an external magnetic field is presented. The soft body of the shuttle-shaped structure microrobot was manufactured from pure Ecoflex, while the skeleton for magnetic actuation was manufactured from Ecoflex and NdFeB composites in a certain ratio and was endowed with a special magnetization profile. Microrobots that experience external magnetic fields are able to swim underwater and have environmental adaptations that include the flexibility to traverse aquatic plants area and crushed stone terrain. The robot also exhibits friendly interactivity and camouflage ability to get close to the zebrafish without scaring them. Moreover, the soft miniature robotic fish could be used to study the impacts of the morphology and kinematics changing in zebrafish populations.