Biomedical micro/nanorobots as active delivery systems
with the
features of self-propulsion and controllable navigation have made
tremendous progress in disease therapy and diagnosis, detection, and
biodetoxification. However, existing micro/nanorobots are still suffering
from complex drug loading, physiological drug stability, and uncontrollable
drug release. To solve these problems, micro/nanorobots and nanocatalytic
medicine as two independent research fields were integrated in this
study to achieve self-propulsion-induced deeper tumor penetration
and catalytic reaction-initiated tumor therapy in vivo. We presented
self-propelled Janus nanocatalytic robots (JNCRs) guided by magnetic
resonance imaging (MRI) for in vivo enhanced tumor therapy. These
JNCRs exhibited active movement in H2O2 solution,
and their migration in the tumor tissue could be tracked by non-invasive
MRI in real time. Both increased temperature and reactive oxygen species
production were induced by near-infrared light irradiation and iron-mediated
Fenton reaction, showing great potential for tumor photothermal and
chemodynamic therapy. In comparison with passive nanoparticles, these
self-propelled JNCRs enabled deeper tumor penetration and enhanced
tumor therapy after intratumoral injection. Importantly, these robots
with biocompatible components and byproducts exhibited biosecurity
in the mouse model. It is expected that our work could promote the
combination of micro/nanorobots and nanocatalytic medicine, resulting
in improved tumor therapy and potential clinical transformations.