Micromanipulation techniques struggle to achieve three-dimensional rotational control at the microscale without compromising biocompatibility or spatial flexibility. Conventional methods based on mechanical contact, optical forces, or confined microfluidics constrain dynamic reconfiguration and surgical accessibility. Here, we introduce a dual-bubble acoustic micromanipulator that enables multidirectional rotation through controlled hydrodynamic fields. By placing oscillating microbubbles at the tips of micropipettes, this system creates adjustable vortex patterns: a single microbubble generates toroidal flows for out-of-plane rotation, while two microbubbles produce shear forces for in-plane spinning. This approach uses simple mechanical adjustments to control rotational axes in open fluid environments, without needing frequency modulation or phase synchronization. Flow-field simulations and experiments with polystyrene microspheres confirm deterministic orientation control, and tests with shrimp embryos demonstrate rotation at clinically relevant speeds. The open architecture integrates seamlessly with standard microscopy and robotic injection systems, offering a non-contact, precise tool for applications such as polar body alignment, intracellular surgery, and 3-D imaging.

Micromanipulation techniques that can achieve controlled fine operations at the micro scale play an important role in biomedical fields including embryo engineering, gene engineering, drug screening, and cell analysis. However, micromanipulation of biological micro-objects, such as cells and micro tissues, suffers from mechanical damage and low efficiency. Several techniques have been introduced to manipulate cells more easily, but most of them are restricted by expensive devices, limited work area, and potential damage to cellular structure. Here we develop a hydrodynamic manipulation method to rotate and transport mouse oocytes, which utilizes acoustic waves and micropipette to generate acoustic radiation force and excite microstreaming. This method can accomplish rotational and translational operations precisely and controllably. We tested the process of trapping, rotation, and transportation of the mouse oocytes, and measured rotational and translational speed with a range of applied voltage. The method was able to shorten the cost time of delivery and posture adjustment before oocyte injection. Our study provides an easy-to-use technique for oocyte manipulation without contact, and it has the potential to be universally applied in many cellular studies.

The magnetic microrobot has become a promising approach in many biomedical applications due to its small volume, flexible motion, and untethered micromachines. The micro-chain robot is one of the most popular magnetic microrobots. However, the uncontrollable magnetic moment direction and quantity of the magnetic beads consisted in the existing self-assembled micro-chain robot limit their locomotion and applications. This paper proposed an on-chip micro-chain robot fabrication method to assemble the magnetic beads with controllable magnetic moment direction and quantity. The bead quantity can be controlled by the structure limits of the microchannel, and the direction of the magnetic moment can be adj usted by the integrated external magnetic field. The assembled magnetic beads are then glued by the hydrogel under UV exposure. The micro-chain robots with different quantities and magnetic moment directions of the magnetic beads were successfully fabricated and tested in experiments. Due to the array structure of the microfluidic device, batch manufacturing of low-cost magnetic robots was achieved in our method. The movement of dual-bead microrobots with two orthogonal magnetic moment directions was analyzed and compared. One of the dual-bead microrobots was applied in the transportation of the hydrogel module using pushing and pulling modes. It indicated that the proposed controllable on-chip fabrication of the magnetic micro-chain robots has the potential to enhance the microrobot ability in biomedical applications.