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Developing microrobotic systems for accurate and fast manipulation of microobjects or living cells has the potential to significantly advance biomedical and microfabrication applications. Despite recent progress in this field, comprehensive multistimuli responsive, fast, and precisely controllable microrobots remain limited. In this study, automated position and speed control of acoustically powered, bubble‐based, magnetically steerable microrobots is demonstrated, along with micromanipulation of mammalian cells using these microswimmers. Enhanced control of the microswimmers is achieved by designing and implementing a closed‐loop control system that guides the microrobots along a predetermined path while modulating their speed by adjusting the acoustic frequency near the resonant value. The microrobots are guided to cells, enabling cell manipulation by pulling them with the microrobots. Overall, the results highlight the capability and controllability of these magnetically and acoustically responsive microrobots for future cell‐based applications, including manipulation, delivery, and microsurgery. 

Abstract Micro‐sized magnetic particles (also known as microrobots [MRs]) have recently been shown to have potential applications for numerous biomedical applications like drug delivery, microengineering, and single cell manipulation. Interdisciplinary studies have demonstrated the ability of these tiny particles to actuate under the action of a controlled magnetic field that not only drive MRs in a desired trajectory but also precisely deliver therapeutic payload to the target site. Additionally, optimal concentrations of therapeutic molecules can also be delivered to the desired site which is cost‐effective and safe especially in scenarios where drug dose‐related side effects are a concern. In this study, MRs are used to deliver anticancer drugs (doxorubicin) to cancer cells and subsequent cell death is evaluated in different cell lines (liver, prostate, and ovarian cancer cells). Cytocompatibility studies show that MRs are well‐tolerated and internalized by cancer cells. Doxorubicin (DOX) is chemically conjugated with MRs (DOX‐MRs) and magnetically steered toward cancer cells using the magnetic controller. Time‐lapsed video shows that cells shrink and eventually die when MRs are internalized by cells. Taken together, this study confirms that microrobots are promising couriers for targeted delivery of therapeutic biomolecules for cancer therapy and other non‐invasive procedures that require precise control.