Robotic non-contact three-dimensional (3-D) micromanipulation of micro-objects is critical for micro-assembly applications, but achieving high precision and reliable release in the microscale remains challenging. Traditional contact and non-contact techniques face limitations in automated 3-D operation. We present a fully automated micromanipulation system using an acoustic bubble end-effector for non-contact 3-D handling of microbeads. The system integrates real-time vision feedback with Z-axis autofocus and adaptive proportional-integral-derivative control for precise trapping, transport, and release. Leveraging localized bubble-driven microstreaming and acoustic radiation forces, our end-effector forms a stable trap within 100 ms and transports microbeads at speeds up to 1 mm/s. Experiments demonstrate exceptional 3-D dexterity, with trapping success rates consistently greater than 80% for microbeads of 60-120 μm diameter, and release placement accuracy is confirmed to be within ±2.5 μm when operating below a 150 μm height. The system achieves broad size adaptability and operates in free-space 3-D environments, overcoming workspace constraints of microfluidic setups. By eliminating mechanical contact, this approach reduces contamination and damage while delivering precise 3-D control often lacking in other non-contact methods. Our system bridges acoustofluidics and robotic automation, offering a versatile solution for automated micro-assembly and biomedical applications.

Microrobots have garnered significant attention due to their vast potential applications across various fields. Among various types of microrobots, piezoelectric robots stand out due to their exceptional motion accuracy, low power consumption, and simple structural design. This work introduces a novel piezoelectric microrobot, the Dual-Modal Piezoelectric Robot (DMPBot), which is fabricated with an innovative carbon fiber substrate through a heat-pressing process with a compact size of 6 mm × 9 mm × 1.1 mm and a weight of only 0.05 g. DMPBot can achieve both high-speed and high-precision motion in non-resonant mode, as well as omnidirectional movement by integrating non-resonant and resonant modes. In non-resonant mode, the robot can reach a speed of 33 mm/s (3.67 body lengths per second) and a sub-micron resolution of 0.4 μm by adjusting the applied signal. This work presents an analysis of the design, fabrication, and performance of DMPBot, focusing on its dynamic response, motion mechanisms, high-speed and high-precision motion, and omnidirectional movement capabilities. Experimental results validate the ability of DMPBot to perform high-speed, high-precision, and omnidirectional motion, demonstrating its promising potential in the field of micromanipulation.

During the past decade, DNA origami has emerged as a promising technology to construct DNA nanorobots with programmable configurations and excellent biocompatibility. However, existing DNA origami-based nanorobots exhibit weak stability in complex biological environments and lack efficient delivery capabilities when serving as drug carriers. This study introduces a reconfigurable tetrahedral DNA nanorobot, whose conformational transition pathways are validated by multi-resolution molecular dynamics simulations. Building on this, we systematically analyzed the structural stability of the tetrahedral nanorobot using multiple simulation methods. We then fabricated the specific molecule-triggered tetrahedral DNA nanorobot with high structural stability and efficient drug delivery capacity. The proposed nanorobot was further employed for the recognition and inhibition of circulating tumor cells. These results highlight the application potential of the proposed DNA origami-engineered nanorobot in biomedicine and nanosensing.

Traditional single-cell mechanical characterization techniques (e.g., atomic force microscopy) often face limitations in throughput, require invasive labeling, or fail to replicate physiological microenvironments, impeding their clinical utility for rapid cancer cell analysis. To address these limitations for automated characterization of cellular mechanical properties, this study proposes a novel method using microchannels with narrow geometric structures to measure cellular mechanical characteristics. A dynamic mechanical characterization technique with serially connected microchannels simulates malignant tumor cell deformation and migration in vivo, enabling precise identification of three malignant tumor cell lines and three normal cell lines through consecutive compressions. High-speed imaging combined with computer vision and image processing techniques facilitates rapid and accurate automated analysis for tumor cells. Furthermore, this study reveals that the mechanical properties of the cell nucleus determine the overall cellular mechanics, with the differences between tumor and normal cells attributed to variations in nucleus mechanics. This approach shows promise for early cancer diagnosis.

Micro-nano robots must break the symmetry of the flow field to generate net displacement in the low Reynolds number environment. The spherical micro-robots utilize the frictional forces generated through interaction with the surface. We designed a magnetic microroller robot powered by the rotating AC magnetic field. Here, we employed dual measurements of laser ranging and computer vision to demonstrate that a single 100 μm microroller maintains a lubrication film of 1 to 15 μm with the surface during normal motion. We found that the translational velocity of the microroller is correlated with the lubrication film thickness. Based on the robot's gravity, we controlled an additional downward gradient magnetic field to effectively increase the load of robot and reduce the lubrication film thickness, thereby controllably increasing the translational velocity of the robot. For example, the gradient magnetic field generated by superimposing a 30mA direct current input can reduce the lubrication film thickness from 8 μm to 4 μm in a 10 Hz rotating magnetic field, and increase the translational velocity from 230 μm/s to 460 μm/s. The enhancement of the robot's motion performance enables it to better control its movement in fluids. Finally, we validated the strategy for controllable acceleration of micro-scale particles rolling on surfaces, applied to control fluid motion in multiple arteries within blood vessels. These results offer deeper insights into the physical motion mechanism of surface robots and hold significant implications for future applications in biomedical engineering.

Chemical reactions constitute a cornerstone of fundamental scientific inquiry, yet traditional methodologies and platforms are encumbered by excessive reagent and consumable demands. Emerging alternatives, such as microfluidic systems, while innovative, suffer from intricate fabrication processes and elevated costs associated with operator training. Other contemporary approaches face limitations including reagent compatibility constraints and prohibitively expensive instrumentation. To address these challenges, this study introduces a contactless chemical reaction platform leveraging an ultrasonic vortex field to achieve stable capture, microscale droplet transport, and sequential multi-droplet mixing without direct contact. This platform substantially reduces contamination risks, minimizes reagent and consumable usage, accommodates a broad spectrum of reagent types, and imposes minimal demands on operator expertise. Demonstrating robust performance in microdose reaction control, the system offers significant potential for advancing chemical research and its applications.

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.

A magnetically controlled catheter system is proposed to enhance the precision and safety of vascular interventions by reducing procedure time and radiation exposure. The system can also function as a support channel for guidewire deployment. A novel navigation approach is introduced, employing an external permanent magnet capable of controlled rotation to actuate a catheter with an embedded magnetic tip. Leveraging magnetic coupling and a redundant rotational DoF, the system achieves fine angular tip control with minimal spatial displacement, significantly enhancing maneuverability in constrained vascular environments. The magnetic field distribution and its influence on catheter response are characterized, and a kinematic model of the actuation mechanism is established. Experimental validation is conducted under varying magnetic field strengths and orientations, demonstrating reliable steering performance. Application-based experiments in simulated clinical environments further confirm precise navigation capability. The results highlight the advantages of rotational magnetic control in enhancing flexibility and accuracy. The proposed system presents a promising solution for automating catheter-based interventions, offering improved efficiency and power in minimally invasive procedures.

Microassembly plays an important role in fabricating complex structures with small basic components in industrial and biomedical fields. Inverted optical microscope could provide high-quality image feedback for microassembly with its continuously improving resolution. However, a compact stage capable of positioning and reorienting micro-objects while fitting within the limited space under an inverted optical microscope remains unavailable. This paper proposes a compact R-X-Y stage that can transport micro-objects over long distances in the X and Y directions, and reorient the objects by the 360-degree continuous rotation. Additionally, different from commonly putting the rotational stage on the X-Y stage, we mount the thin X-Y stage on a rotational stage. Thus, after aligning the centers of the visual field and rotational stage at the beginning, all the visiable micro-objects will not move out of the visual field during the rotation. We further integrate the R-X-Y stage and the dual-finger micromanipulator, and then use them to assemble 2-D patterns and complex 3-D micromachine. The obtained results and preliminary demonstration indicate that the proposed compact R-X-Y has great potential in assembling complex micromachines.

The development of magnetic soft microrobots has been constrained by the lack of precise control of microactuator’s programmability. To address such an issue, we use a piezo-driven two-fingered microhand to selectively position the magnetic microactuators within a soft scaffold. Each microactuator is sequentially oriented to a desired direction through surface rotation by applying magnetic field–based torques, and is then fixed to the scaffold using ultraviolet (UV) cross-linking. A detailed analysis is conducted on the spatial positioning capability of the microhand’s parallel mechanism and the magnetic programming performance of electromagnetic coils’ orientation control. To overcome the inefficiency and inaccuracy of labor-intensive manual assembly, we propose an automated assembly strategy to create magnetic soft-bodied microrobots following our design. The multiple fabricated microrobot prototypes exhibit programmed 2D and 3D shape transformations and various robotic gaits for surface locomotion. This strategy can enable the rapid fabrication of multimaterial 3D magnetic microrobot designs with potential applications in robotics, biomedical engineering, and environmental governance. Note to Practitioners—The motivation of this work is to address the limitations in current fabrication methods for magnetic soft microrobots, which include 3D printing, heating, mold casting, and chemical synthesis. These approaches fall short when creating microrobots with arbitrary structures, multimaterial compositions, and complex magnetization profiles. Micro-assembly offers a potential solution, yet existing techniques depend on either time-consuming manual assembly or costly equipment lacking sufficient flexibility for 3D spatial manipulations. In this work, a 3-degree-of-freedom, high-precision parallel microhand-based assembly method is proposed. The microhand provides high precision and speed for rapid positioning of assembly modules, while electromagnetic coils enable precise orientation in magnetization programming. Experimental results confirm the effectiveness of this method and demonstrate the robustness and adaptability of the automated fabrication strategy. This approach facilitates the fabrication of magnetic soft microrobots with specific deformation and locomotion capabilities according to design intent.

In recent years, micromanipulation technology has achieved extensive applications in industry and life science. Improving the precision and bandwidth of the micromanipulator and simultaneously reducing size, weight, and cost pose significant challenges to the existing micromanipulator design and fabrication methods. Here, we propose a 3-RRS micromanipulator with an origami-inspired spherical joint based on the PC-MEMS process, aiming for miniaturization and cost-effectiveness. The spherical joint allows rotations of 140° around the x-axis approximately, 140° around the y-axis approximately, and 20° around the z-axis approximately. The micromanipulator has weights of 0.8 g, dimensions of 16 mm × 16 mm × 22 mm, and workspace of 0.7 mm3. The end platform of the micromanipulator can be equipped with various effectors to accomplish different kinds of tasks. Experimental results validated its high precision and bandwidth, exhibiting its potential to perform intricate micromanipulation tasks.

Micro-assembly is an emerging method to fabricate microrobots with multiple modules or particles. However, there is always a lack of a flexible and efficient method to freely create the desired magnetic soft microrobots. In this paper, an automated assembly system based on a two-fingered microhand is presented for fabricating magnetic soft microrobots. Our proposed system can automatically pick and place components to assemble microrobots with a two-fingered micromanipulator, and orient these components through an external magnetic field. The automated assembly has the advantages of high accuracy, high speed, and high success rate. It can endow magnetic microrobots with flexible material selection, arbitrary geometry design, and programable magnetization profile. We can make full use of this system to fabricate multiple magnetic soft microrobots. The experiment results demonstrate that this system can efficiently fabricate microrobots with excellent mechanical properties, which have application potential in robotics, biomedical engineering, and environmental governance.

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.

In the last decade, researchers have been trying to develop many microrobots that mimic the extraordinary abilities of bionts in complex environments. How to fabricate the biomimetic microrobot with satisfying deformability and complex shapes to realize desired precise motion is the key issue. In this paper, we proposed an efficient programable fabrication method of the magnetic soft micro-robot through an on-chip photopolymerization system. The superparamagnetic nanoparticles were compiled according to the magnetic anisotropy and assembled in the micro-robot. Then these nanoparticles were immobilized by photopolymerization of the hydrogel polymer. With this fabrication method, a joint rotation mechanism was first fabricated to characterize the deformation performance under the magnetic field control. Besides, the snake-like micro-robot were also fabricated, and the desired motions were achieved. The experimental results show that the proposed programable on-chip fabrication of magnetic soft micro-robot has the potential to facilitate the development of magnetic microrobots and their applications in the biomedical field.

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.

Microfluidic devices for cell immobilization have significantly advanced the biological analysis at the single-cell level. However, the previous research on immobilization of multiple single cells, especially with deterministic quantities, is insufficient. In this paper, we proposed a novel microfluidic device based on the passive hydrodynamics and the uniform geometric design principle, which can array different numbers of cells in every capture cavity. The capture cavities could be stretched to accommodate more cells, and the trapping force was adjusted by modifying the related geometric parameters of the inside channel. The whole procedure was monitored and further automatized by integrating computer vision technology under a microscope. On the proposed integrated on-chip platform, we realized full-automated arraying of a single cell, two cells, and three cells on a single chip, achieving success rates up to 95%, 75%, and 72%, respectively. As a primary experimental demonstration, the cell viability test of arraying multiple cells with different quantities showed excellent biocompatibility and no significant association between trapping quantity and cell survivability. We envision that the proposed quantity-controllable, high-efficiency microfluidic devices for multiple cell arraying could be a powerful platform for an in-depth study of cell heterogeneity and cell communication between multiple cells.Note to Practitioners—This article is motivated by the biomedical applications of multi-cell arraying. The designed microfluidic devices employ passive hydrodynamics, and the capture cavities are stretched to accommodate different numbers of cells. The whole arraying procedures are automatized using computer vision technology. Simulations and experiments demonstrate the high efficiency, controllability of the cell quantity, and excellent biocompatibility.

In this paper, an automated tracking system with head and tail recognition for time-lapse observation of free-moving C. elegans is presented. In microscale field, active C. elegans can move out of the view easily without an automated tracking system because of the narrow field of view and rapid speed of C. elegans. In our previous works, we constructed an automated platform with 3D freedom to track centroid region of the nematode successfully. However, tracking time was not long enough to support a full time-lapse observation. Our proposed system in this study integrate the detection method in horizontal plane with depth evaluation more tightly. Tracking time and response speed have been greatly improved. Besides, we make full use of curvature calculation to make the system recognize the head and tail of C. elegans and the recognition rate can be up to 95%. The results demonstrate that the system can fully achieve automated long-term tracking of a free-living nematode and will be a nice tool for C. elegans behavioral analysis.

Capillary Ionic Transistor (CIT) is introduced as a nanodevice which provides control of ionic transport through nanochannel by gate voltage. CIT is Ionic transistor which employs pulled capillary as nanochannel with tip diameter smaller than 100 nm. We observed that gate voltage applied to gate electrode, deposited on the outer wall of capillary, affect a conductance of nanochannel, due to change of surface charge at the solution/capillary interface. Negative gate voltage corresponds to lower conductivity and positive gate increase conductance of the channel. This effect strongly depends on the size of the channel. In general, at least one dimension of the channel has to be small enough for electrical double layer to overlap. As a demonstration of the gate control ability, we performed Si nanoparticle delivery via CIT and recorded the deliverance through resistive pulse method. Size and velocity measurement are also conducted, to showcase the versatility of CIT device.

We have successfully achieved manipulation and assembly of microbeads having the size of 100μm diameter by hemispherical end-effectors with high stability and accuracy. The motivation of achieving assembly of actual cells lies in the great significance of it in tissue regeneration and cell analysis. Firstly, the most difficult problem we need to solve is the releasing problem caused by adhesion force. The viscosity on cell surface is much larger than the microbeads which makes cell releasing challenging. Secondly, the cell can generate its deformation, then contact area with end-effector will change during grasping process. This may influence the adhesion force and also bring problem to releasing. Thirdly, cell is much smaller, around 15μm in diameter, so we need to fabricate smaller end-effector to achieve successful manipulation and ensure the stability in the meantime. In this paper, we realize the manipulation by decreasing the adhesion forces and apply vibration to release a cell stably. We found the appropriate scale size for the end-effector is around 10μm diameter. It can not only grasp a 15μm cell but also bring little interference to the environment. As a demonstration of the proposed manipulation method, the repeated experiments were conducted to explore the dependence of adhesion force on the grasping distance, which can be helpful in the improvement of successful rate. Finally, we achieved automatic cell assembly using Hela cells.

Nowadays single cell analysis becomes a more and more important method to gather the information of individual cells and study the heterogeneity of cells caused by random expression of gene, protein and the level of metabolism. Many device and technologies of single cell analysis have been developed to meet these needs. In this paper, we presented a high-throughput microchannel for single cell immobilization with small sheer pressure. It features high density arrays, which can accommodate up to 130~300 traps within 1~2 mm2. According to our experiment, about 91% of capture unit can be occupied by the single cell in 40 s, using the optimized structure of microchannels. Therefore, we expect that the high throughput microchannels can be of great importance for the biological research.

In micromanipulation, lots of methods have been developed to manipulate objects in microscale. However, few of them can be applied in both the transportation and the rotation of the micro objects. In this paper, we present a novel method to realize the non-contact transportation and rotation of the micro objects based on the vibration-induced swirl flow. A piezo actuator is set between the glass needle and a metal rod. The sine wave with controlled frequency and amplitude is input into the piezo actuator to drive the glass needle to move circularly, which is caused by resonance of the actuator and the metal rod. We place the glass needle under water and keep a limited distance to the bottom. The circular vibration of the glass needle can generate a swirl flow and low pressure around it. The low pressure can trap and transport the micro objects vertically to the glass needle, and the swirl flow can rotate the objects continuously. Finally, we realize the trap and rotation of micro object with only one piezo actuator. Experiments of transportation and rotation of microbeads are carried out, and the results demonstrate it is a simple, low-cost, effective micromanipulation method.

Helical structure assembled by hydrogel microfibers is significant for culture of smooth muscle cells. However, the helical structure is only fabricated at the macroscale, while the fabrication of helical microstructure is still a challenge due to the lack of assembly method. In this paper, we propose a robotics-based assembly method to handle such challenge. An electromagnetic needle (EMN) is employed as end-effector to magnetically reel the microfiber encapsulating magnetic nanoparticles around a micropillar, and a dual-ring structure is designed to keep the microfiber being attracted at the EMN tip. For enhancing the stability of tip attraction, the manipulation mode of anticlockwise pushing microfiber is established. Moreover, the interaction mechanism between EMN tip and microfiber is analyzed by developing a static force model, and then the key condition of stably reeling microfiber is concluded. Furthermore, a robotics-based motion trajectory of EMN tip is planned to achieve a smooth reeling process. Based on such planning, the size of dual-ring structure is further optimized to improve the success rate of reeling. Finally, the helical microstructure with there-turn coils is successfully fabricated.

Fabrication of artificial blood vessels in micro scale significantly benefits the regeneration of functional human vascular networks. In this paper, we develop an efficient multi-microrobotic system with an innovative motorized sample holder (MSH) and two manipulators. Air is injected into the solution through a glass pipette fixed on one manipulator to create bubbles. These bubbles conduct a regular rising movement, which is utilized to assemble the 2D ring-shaped microgels fabricated in a simple micro fluidic device. With this novel bubble-based method and the robotic system, we achieve the automation of the assembly. A 1.2 mm long vascular-like microtube with an outer diameter of 200 μm is fabricated. The whole process of the bubble-based assembly is visually observed and analyzed with side view. Key parameters are characterized to improve the assembly. Results show that the automated bubble-based assembly success rate is 100% and average time cost of assembling every microgel is as low as 3.25s.