Programmable ultrasound-mediated swarms manipulation of bacteria-red blood cell microrobots for tumor-specific thrombosis and robust photothermal therapy.

Abstract

Despite the excellent advantages of biomicrorobots, such as autonomous navigation and targeting actuation, effective penetration and retention to deep lesion sites for effective therapy remains a longstanding challenge. Here, we present dual-engine cell microrobots, which we refer to as PR-robots, created by conjugating photosynthetic bacteria (PSB) with red blood cells (RBCs). The robots penetrate the tumor interior in swarms through combined hypoxic traction and ultrasound actuation (UA). The hypoxia-targeting ability of PSB induced PR-robot accumulation in the tumor region. Subsequently, programmable UA trapped the PR-robots to form bioswarms and traverse tissue obstacles, penetrating the tumor interior. The substantial influx of PR-robots into the tumor tissue promoted the formation of tumor-specific thrombus (TST). Finally, the PSB and TST synergistically improved the effect of photothermal therapy. Thus, these advantages of remote ultrasound control technology pave the way for various new therapies in practical biomedicine.