Micromanipulation System Research Articles

Development and Testing of a Dual-Driven Piezoelectric Microgripper with High Amplification Ratio for Cell Micromanipulation

Cell micromanipulation is an important technique in the field of biomedical engineering. Microgrippers play a crucial role in connecting macroscopic and microscopic objects in micromanipulation systems. However, since the operated biological cells are deformable, vulnerable, and typically distributed in sizes ranging from micrometers to millimeters, it poses a huge challenge to microgripper performance. To solve this problem, this paper develops a dual-driven piezoelectric microgripper with a high displacement amplification ratio, large stroke, and parallel gripping. By adopting modular configuration, three kinds of flexure-based mechanisms, including the lever mechanism, Scott–Russell mechanism, and parallelogram mechanism are connected in series to realize three-stage amplification, which effectively makes up for the shortage of small output displacement of the piezoelectric actuator. At the same time, the use of the parallelogram mechanism also isolates the parasitic rotation movement, and realizes the parallel movement of the gripping jaws. In addition, the kinematics, statics, and dynamics models of the microgripper are established by using the pseudo-rigid body and Lagrange methods, and the key geometric parameters are also optimized. Finite element simulation and experimental tests verify the effectiveness of the developed microgripper. The results show that the developed microgripper allows an amplification ratio of 46.4, a clamping stroke of 2180 μm, and a natural frequency of 203.1 Hz. Based on the developed microgripper, the nondestructive micromanipulation of zebrafish embryos is successfully realized.

Enabling intuitive and effective micromanipulation: A wearable exoskeleton-integrated macro-to-micro teleoperation system with a 3D electrothermal microgripper

In this article, we present a novel teleoperation system for dexterous micromanipulation with a 3D three-fingered electrothermal microgripper. A lightweight wearable exoskeleton hand is designed and employed as the primary device, integrating rotational potentiometers as angle sensors, which are embedded in a closed-loop kinematic chain for detecting flexion/extension and adduction/abduction angles of motion. The measured angles are subsequently translated into exoskeleton hand-fingertip positions utilized as the primary inputs. A 3D electrothermal microgripper based tele-micro manipulation system is realized. The displacement of the exoskeleton fingertips is harnessed to govern the actions of the microgripper via an effective position incremental control method. Furthermore, the system's capabilities are exemplified through intricate micromanipulations performed on soft zebrafish embryos. The micromanipulations encompass gripping and rotational maneuvers. The outcomes of empirical experimentation clearly demonstrate the suitability of the macro-micro teleoperation system, which incorporates an exoskeleton hand for controlling a microgripper in 3D micromanipulation. The system improves operator comfort and maneuvering efficiency. Even for untrained users, the tasks can be accomplished with ease in an intuitive and effective way.

O-185 Far away so close: remote ICSI using an AI-powered robot

Abstract Study question Can intracytoplasmic sperm injection (ICSI) be performed remotely using a personal computer and an intelligent robotic micromanipulation system? Summary answer An AI-enhanced robotic micromanipulation system was developed that allows successful remote execution of ICSI by experts or non-experts. What is known already ICSI has become the method of choice for fertilization of eggs during IVF, but it remains technically demanding, requiring manual control of highly specialized equipment by expert embryologists. Limited automation of the procedure has been achieved but most steps are still performed manually. Remote performance of ICSI has never been attempted. Study design, size, duration To achieve automated ICSI, we explored individual commands for each step, issued from an offsite computer. Steps included AI-assisted sperm selection, laser immobilization, random oocyte positioning, opening a path in the zona pellucida prior to needle entry, and Piezo-mediated oolemma breakage. The modified protocols were optimized using mouse oocytes and mouse sperm and then tested using the automated system to inject hamster oocytes with human sperm. Finally, the system was evaluated in consenting patients. Participants/materials, setting, methods The system consists of an inverted microscope, a motorized stage, motorized micromanipulators, laser, piezo-electric actuator, and microinjectors, all controlled by proprietary digital and AI-driven software. Development of this system was a collaborative effort across four countries in three laboratories, including an engineering and embryo research facility, an experimental embryology laboratory, and an IVF clinic. The pilot clinical procedures were performed after full IRB review and trial registration. Main results and the role of chance To assess the safety of using a laser on sperm tails for immobilization, manual ICSI was performed on mouse oocytes with mouse sperm immobilized using different laser settings. Once the method was optimized, fertilization (n = 176, 98.8%) and blastocyst formation (80.7%) in the experimental group were similar to those in the controls without laser (n = 173, 99.4% and 80.6%, respectively) (p > 0.05). Subsequently, 90 blastocysts from the experimental group were transferred to pseudopregnant mice resulting in 40.4% live pups. This was comparable to the results with control embryos (n = 90, 47.8%) (p = 0.098). The remotely controlled robotic system was then tested in hamster oocytes, demonstrating survival (n = 102, 94.1%) similar to the manually injected control group (n = 102, 97.1%) (p = 0.3). In the clinical pilot trial in four patients, 22 oocytes were assigned to remote ICSI, achieving survival (95%), fertilization (81%), and blastocyst formation (65%) comparable to manually performed ICSI controls on sibling oocytes. These results are within the benchmark values established in the Vienna consensus. Throughout all experiments, the system allowed users to successfully perform ICSI remotely issuing commands by pressing single buttons on a computer screen from various locations, ranging in distance from a few meters to over 9,000 kilometers away from the laboratory. Limitations, reasons for caution This experimental ICSI system requires operators in the laboratory to insert and position the microtools and handle the eggs and sperm before and after ICSI. The system also requires a broadband internet connection with at least 50MBPs speed in upload and download. Latency or delayed reaction is a rare possibility. Wider implications of the findings The functionality of a remotely controlled automated ICSI system was validated. The system demonstrates efficiency gains, even with remote operation. The procedures can be programmed to achieve full microscopic ICSI using a single command. This system represents a significant advancement in automation of IVF. Trial registration number Clinicaltrials.gov: NCT06074835 IRB approval: RA-2023-01 IRB ID: CONBIOÉTICA-09-CEI-001-20170131

Quality and Quantity Control of Mitochondria Injection Into Single Cells With Robot-Aided Micro-Manipulation System

Mitochondrial dysfunction plays a significant role in the development of fatal diseases such as aging, cancer, and Alzheimer’s. Transferring mitochondria to cells is a new and potential treatment for mitochondrial DNA (mtDNA)-related illnesses. This article describes a novel technique to control the quality and quantity of mitochondria injected into single live cells using a robot-aided microneedle and optical tweezers (OTs)-based micromanipulation system. Isolated mitochondria and cells are patterned in a 1-dimensional (1-D) array in a microfluidic device, and a robot-aided microneedle collects the predefined number of functional mitochondria with the help of OTs. Then, the microneedle precisely and non-invasively injects these collected mitochondria into single live cells. Given that the two manipulation tools of OTs and microneedle were used, a switch controller strategy is developed to enable mitochondria trapping and injection with OTs and microneedle-based micromanipulator, respectively. The effectiveness of the developed robotic system is experimentally demonstrated with automated injections of isolated mitochondria into HeLa and mesenchymal stem cells (aMSCs). A precise and efficient quality and quantity control of mitochondria injection was possible by using Ots in conjunction with microneedle and microfluidics technologies. Quality-and quantity-controlled ability is analyzed and compared with the traditional mitochondria transfer method (co-culture). Biological tests are further conducted to assess the viability of mitochondria recipient cells. Experimental results demonstrate that the developed system can non-invasively transfer healthy mitochondria into single live cells while precisely controlling the quantity and quality of injected mitochondria. The proposed mitochondrial transfer method has the potential to advance precision medicine methods, particularly for cellular therapy of (mtDNA)-related diseases. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This study was motivated by the problem of inefficient methods of mitochondria injection into single, small, living cells. Due to the issue of microneedle clogging, existing mitochondria injection methods can only inject mitochondria into cells with a 0.3 to 2% efficiency. To address this issue, we have developed an automated method of mitochondria injection into cells that can inject mitochondria into single cells non-invasively with an efficiency of up to 80 %. Existing methods of mitochondria injection also ignored the heterogeneity of mitochondria, such as functionality and the precise number of mitochondria prior to injection. Our methodology can efficiently and precisely control the quality and quantity of mitochondria injection into single cells, which can be useful for the discovery of new information concerning precision medicine, particularly in diseases associated with mtDNA.

Prussian blue nanofilm-sensitized plasmonic electrochemical microscopy for spatially resolved detection of the localized delivery of hydrogen peroxide

Hydrogen peroxide (H2O2) sensing has been widely investigated using various electrochemical methods, yet the challenge of finding an imaging technique capable of real-time, spatially resolved detection remains. Addressing this, we introduce a Prussian blue (PB) nanofilm-sensitized plasmonic electrochemical microscopy (PEM) technique that successfully visualizes the localized delivery of H2O2. The PB nanofilm was carefully characterized, and its sensing capability towards H2O2 was demonstrated in amperometric mode. Employing a precise micromanipulator system, we controlled a micropipette to create a localized concentration gradient on the sensor surface and monitored the gradient through the PB nanofilm-sensitized PEM. The accuracy of the obtained concentration values was further validated by numerical simulations based on finite-element methods. Our technique ensures dependable localized detection, and we anticipate that advancements in film uniformity will further improve the resolution. The potential applications of this technique are broad and significant, including the opportunity to investigate single-cell exocytosis with neurotransmitters like dopamine, thus offering a promising avenue for future biomedical research.

Dynamic modeling and optimization of mechanical drift for compliant parallel micromanipulation driven by V-shape linear ultrasonic motors

Designing micro-mechanisms that satisfy large strokes, high precision, and multiple degrees of freedom has consistently been a research focus and challenge in the field of micromanipulation systems. Linear ultrasonic motors (LUMs), with advantages such as millimeter-level travel, nanometer-level motion resolution, and power-off self-locking, significantly contribute to the advancement in the mechanism design of micromanipulation systems. However, the challenge of mechanical drift lacks a comprehensive theoretical analysis to explain its cause and limits its application. This paper presents a mechanical drift modeling method for a compliant parallel micromanipulation (CPM) driven by a LUM. The model primarily focuses on the creep characteristics of the flexure clamp element in the LUM. Based on the stiffness matrix analysis method of the compliant parallel mechanism kinematics, the mechanical drift dynamics model of the CPM is established. The influence of the main structural parameters on the CPM mechanical drift is investigated. The research indicates that the creep of flexure clamps in the CPM is the main factor leading to the mechanical drift. Optimization of mechanical drift is achieved by choosing flexure clamps with higher tangential stiffness for LUM and flexure hinge joints with greater flexibility for CPM. Finally, experimental studies reveal that under equivalent conditions, the mechanical drift of the optimized CPM was significantly reduced than before, proving the rationality of the theoretical model and optimization method.

High-Speed Cell Assembly with Piezo-Driven Two-Finger Microhand

In the past few decades, researchers have conducted extensive studies on cell micromanipulation methods. However, there has consistently been a lack of a micromanipulation system that excels in both precision and speed. Additionally, many of these methods rely on manual control, thus significantly reducing efficiency. In this paper, a robotized micromanipulation system employing a two-finger microhand is proposed. The microhand has a 3-DoF parallel mechanism driven by three piezoelectric actuators, enabling high-precision micromanipulation. Replacing the needle-tip end-effector with a hemispherical end-effector makes cell grasping easier and more stable. In addition, a vibration-based release method combined with gel coating is proposed to reduce the release difficulty caused by adhesion forces. Through multiple sets of experiments, we have determined the optimal grasping and releasing conditions while balancing precision, stability, and damage degree to cells. An automated cell assembly strategy based on microscopic visual feedback and pick-and-place path planning is proposed to achieve the robotized high-speed cell array. Hela cells were chosen as the operation objects, achieving a 95% success rate in grasping and a 97% success rate in releasing. A “T” letter array formed by cells was successfully assembled with an average grasp and release time of less than 0.8 s and an assembly accuracy of 4.5 μm for a single cell. This study holds significant implications for the fields of biology and medicine, presenting potential applications in tissue engineering.

A vibrating capillary for ultrasound rotation manipulation of zebrafish larvae.

Multifunctional micromanipulation systems have garnered significant attention due to the growing interest in biological and medical research involving model organisms like zebrafish (Danio rerio). Here, we report a novel acoustofluidic rotational micromanipulation system that offers rapid trapping, high-speed rotation, multi-angle imaging, and 3D model reconstruction of zebrafish larvae. An ultrasound-activated oscillatory glass capillary is used to trap and rotate a zebrafish larva. Simulation and experimental results demonstrate that both the vibrating mode and geometric placement of the capillary contribute to the developed polarized vortices along the long axis of the capillary. Given its capacities for easy-to-operate, stable rotation, avoiding overheating, and high-throughput manipulation, our system poses the potential to accelerate zebrafish-directed biomedical research.

A Vision-Based Micro-Manipulation System

This research article outlines the design and methodology employed in the development of a vision-based micro-manipulation system, emphasizing its constituent components. While the system is initially tailored for applications involving living cells, its adaptability to other objects is highlighted. The integral components include an image enhancement module for data preparation, an object detector trained on the pre-processed data, and a precision micro-manipulator for actuating towards detected objects. Each component undergoes rigorous precision testing, revealing that the proposed image enhancement, when combined with the object detector, outperforms conventional methods. Additionally, the micro-manipulator shows excellent results for working with living cells the size of yeast. In the end, the components are also tested in a combined system as a proof-of-concept.

Micromanipulator Set-up - Taking Control of This System

Embryo biopsy is a precise procedure, demanding adept manipulation skills and the finest instruments to ensure high-quality results. One of the most crucial elements to gain mastery over is the micromanipulator system. In this session attendees will delve into the practical facets of setting up and controlling a micromanipulator within the context of a blastocyst biopsy. The session will also cover the important aspects of system set-up, instrument alignment, and objective positioning, aimed to maximize control, precision, and stability during the biopsy procedure. Moreover, the discussion will touch on the common challenges faced during the set-up process, offering practical solutions, and troubleshooting tips to manage these effectively.

Remarkable Thermal Conductivity Reduction of Silicon Nanowires during the Bending Process.

The one-dimensional geometry of silicon nanowire helps to overcome the rigid and brittle nature of bulk silicon and enables it to withstand substantial bending stresses. This provides exciting opportunities for the development of flexible electronics. The bending strain introduces atomic displacement in the lattice structure, which inherently has a significant impact on the thermal conductivity. The strain-dependent thermal conductivity of silicon nanowire is crucial to the thermal management and performance of flexible electronic devices. However, in situ thermal conductivity measurement of bending silicon nanowires remains challenging and unreported due to the varying thermal contact resistances between the sample and sensor/heat sink. In this study, the Raman spectroscopy-assisted steady state thermal conductivity measurement method is coupled with a micromanipulation system to successively monitor the thermal conductivity variation of silicon nanowires during the bending process. The result shows that the thermal conductivity of silicon nanowires steeply decreases 55-78% owing to the strain-induced structural deformation during bending. Furthermore, the proposed in situ thermal conductivity measurement method can also be extended to other nanomaterials.

Automated Dissection of Intact Single Cell From Tissue Using Robotic Micromanipulation System

Obtaining single cell from tissues is important for intersection of information and bioscience research. In this article, a robotic framework based on micromanipulation system has been proposed, which can automatically and intelligently cut down single cells intact from tissue sections. The proposed method consists of several steps. An attention mechanism improved (AMI) tip localization neural network is proposed to detect and track the needle tip of micro-scale displacement end-effector within the limited field of view under microscopy. Then, the transformation matrix between the camera and coordinate system of the robot is calculated. And the cutting trajectory is generated and optimized. Finally, the end-effector is controlled to obtain intact single cells from tissues by model predictive control (MPC). The performance of the framework is verified in paraffin tissue sections dissection experiment which shows proposed framework is robust and precise enough to obtain an intact single cell. The error of autonomous single cell dissection is no more than 0.61 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$m$</tex-math></inline-formula> .

Solving the Non-Linear Motion in a Micromanipulation System Powered by Thermocapillary Flows

Non-contact micromanipulation tools have emerged as a promising solution for manipulating small components. However, they are mainly based on non-linear actuation principles requiring ad-hoc control strategies. This paper proposes non-linear control laws to actuate a non-contact manipulation system based on thermocapillary flows for the manipulation of micro-objects on an air-water interface. The actuation system consists of steering a laser beam to locally heat the liquid surface, thus inducing a thermocapillary flow. The resulting flow propels floating objects away from the laser spot with a significant velocity (up to ten body-length per second) but the behavior is highly non-linear. Notably, small errors in the laser positioning are amplified and give place to non-linear motion. Therefore, we developed a control method consisting of a non-linear position controller including a laser position observer. We achieve stable 2D position control in this non-linear system, with a precision of 0.3 mm on a 0.5 mm object.

Correction of Rotational Eccentricity Based on Model and Microvision in the Wire-Traction Micromanipulation System.

In the realm of automatic wire-traction micromanipulation systems, the alignment of the central axis of the coil with the rotation axis of the rotary stage can be a challenge, which leads to the occurrence of eccentricity during rotation. The wire-traction is conducted at a micron-level of manipulation precision on micron electrode wires; eccentricity has a significant impact on the control accuracy of the system. To resolve the problem, a method for measuring and correcting the coil eccentricity is proposed in this paper. First, models of radial and tilt eccentricity are established respectively based on the eccentricity sources. Then, measuring eccentricity is proposed by an eccentricity model and microscopic vision; the model is used to predict eccentricity, and visual image processing algorithms are used to calibrate model parameters. In addition, a correction based on the compensation model and hardware is designed to compensate for the eccentricity. The experimental results demonstrate the accuracy of the models in predicting eccentricity and the effectiveness of correction. The results show that the models have an accurate prediction for eccentricity that relies on the evaluation of the root mean square error (RMSE); the maximal residual error after correction was within 6 μm, and the compensation was approximately 99.6%. The proposed method, which combines the eccentricity model and microvision for measuring and correcting eccentricity, offers improved wire-traction micromanipulation accuracy, enhanced efficiency, and an integrated system. It has more suitable and wider applications in the field of micromanipulation and microassembly.

Modeling and Compensation of Positioning Error in Micromanipulation

In order to improve the positioning accuracy of the micromanipulation system, a comprehensive error model is first established to take into account the microscope nonlinear imaging distortion, camera installation error, and the mechanical displacement error of the motorized stage. A novel error compensation method is then proposed with distortion compensation coefficients obtained by the Levenberg–Marquardt optimization algorithm combined with the deduced nonlinear imaging model. The compensation coefficients for camera installation error and mechanical displacement error are derived from the rigid-body translation technique and image stitching algorithm. To validate the error compensation model, single shot and cumulative error tests were designed. The experimental results show that after the error compensation, the displacement errors were controlled within 0.25 μm when moving in a single direction and within 0.02 μm per 1000 μm when moving in multiple directions.

The Full Model of Micropipette Aspiration of Cells: A Mesoscopic Simulation.

Studies on the interaction between cells and micromanipulation tools are necessary to optimize the procedures and improve the developmental potential of cells. The molecular dynamics simulation is not possible for such a large-scale simulation, and the spring-damped viscoelastic models and the constitutive equationsof the continuum are usually adopted to model the cells as a whole without consideration of the different properties presented by the heterogeneous subcellular components. In this study, we utilized coarse-grained modeling to develop a subcellular model of suspension cell dynamics and a model of a holding micropipette for the fixation of a suspension cell, and designed a large-scale, accurate mesoscopic simulation environment for specific cell micromanipulation. We established a triangular mesh cell membrane and a uniformly distributed, non-intersecting cytoskeleton network and added polymerization/depolymerization processes to connect the cytoskeleton chains with the membrane and cross-linking proteins. In the cell aspiration model, we adopted the profile of the reversed Poiseuille flow to calibrate the viscosity of the fluid and set the bounce-back condition and the appropriate solid-fluid force coefficient to realize non-slip flow at the boundary. The rheological properties of the cells during micropipette aspiration were further analyzed in the simulation by varying parameters such as the inner diameter of the micropipette, negative pressure, and maximum bond length. The model well reproduced the experimentally observed cell deformation phenomenon at low and high pressures. The dynamic response of the cell elongation observed from the simulation was consistent with that obtained from the analysis of the experimental data collected from a custom-designed micromanipulation system. STATEMENT OF SIGNIFICANCE: In this study, we extended the coarse-grained modeling of cells by developing a relatively large-scale micromanipulation environment consisting of a subcellular cell dynamics model and a fluid flow model for cell aspiration. We simulated cytoskeleton filaments that were uniformly distributed in space via applying Harmonic energy to model cytoskeleton with a high level of fidelity. The shortcoming of the soft repulsion in the solid-fluid interaction in the current simulation technique was solved by implementing the bounce-back boundary and the condition that the total force imposed by the wall particles on the fluid particles was equal to the pressure of the fluid. This work paved the way for understanding the mechanical properties of cells and improving the biological efficacy of micromanipulation.

High precision PCB Soldering With Pin Springback Compensation by Robotic Micromanipulation

Through-hole components (THCs) soldering is widely reserved in electronic industry. Although recent progress in soldering robot has greatly improved the productivity, how to deal with metal pins' misalignment with the through-hole center remains a big issue, which may affect the soldering quality, reduce the product reliability, or even result in failure. To address this challenge, this article presents a robotic micromanipulation system and a hybrid visual servoing control strategy with springback compensation. First, we analyze the deformation and recovery phenomenal of the metal pin during alignment and then establish its elastoplastic model and springback model accordingly. In view of high precision and efficiency in electronics assembly, we propose a hybrid control strategy by combining the position-based and image-based visual servoing control, where the former is for approaching the target region efficiently and the latter is for high precision pin alignment. With the developed model and control strategy, the robotic micromanipulation system can automatically detect the pin's position and posture by a microscope camera (magnification 15 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\times }$</tex-math></inline-formula> ) and control the end-effector to align the pin to the through-hole center based on a predicted overshoot. The experimental results verify that our approach can confine the maximum alignment error in three pixels ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula> 37 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\mu }$</tex-math></inline-formula> m) with 100% success rate, which substantially improves the soldering accuracy of current techniques. This article paves a new path for high precision THCs soldering, which will not only directly improve the quality and reliability of PCBs in industry, but also inspire the application of robotics in micromanufacturing and microfabrication.

Capture of microscale objects using the smectic–isotropic phase interfacial force for soft-manipulation devices

We propose a micromanipulator system that traps microparticles using the interfacial force between liquid crystals and isotropic phases. The maximum interfacial force of a nematic liquid crystal (5CB) was previously shown to be insufficiently strong for use in micromanipulator systems. Because a smectic liquid crystal (12CB) has a higher order of molecular alignment, the smectic-isotropic interfacial force is stronger than the nematic-isotropic interfacial force. We demonstrated in the present study that the smectic-isotropic interface was strong enough to capture tungsten carbide particles. The interfacial force of 12CB was approximately 76.1nN, which was more than 13 times stronger than the nematic-isotropic interfacial force of 5CB and 8CB. Thus, the smectic-isotropic interface of 12CB could be exploited for the development of new manipulation or actuation systems. • The interfacial forces between liquid crystal phase interfaces were evaluated. • The smectic-isotopic interfacial force was much stronger than that of other interfaces. • Micromanipulators can be developed using the smectic-isotropic interface.

Micromanipulation System Capable of Simultaneously Presenting High-Resolution and Large Field-of-View Images in Real-Time

Microinjection technology is widely used in biotechnological processes such as gene manipulation and microinsemination. Generally, microinjection is performed under an optical microscope while viewing the video of the targets in real-time. In the microinjection process, multiple oocytes must be placed in the same droplet, for which the injection must be performed multiple times. Furthermore, the target must be observed at different magnifications during injection and the oocyte transfer operation. Hence, the operators are required to change the magnification and light intensity repeatedly. These tasks are complicated and are a burden for the operators. Thus, the accuracy, reproducibility, and productivity of microinjection depend on the operator’s skill level. In this study, to reduce the burden on the operator and simplify the operation of microinjection, we propose a micromanipulation system that enables both wide-range and high-resolution video presentation with free viewpoint selection. The proposed micromanipulation system is based on a view-expansion microscope system with simultaneous multi-view imaging. We verify the effectiveness of the proposed system by evaluating the resolution of images presented to the operator and through the experiments involving moving microbeads performed by inexperienced subjects.

Micropipette-assisted atomic force microscopy for single-cell 3D manipulations and nanomechanical measurements.

Mechanical cues play a crucial role in regulating physiological and pathological processes, and atomic force microscopy (AFM) has become an important and standard tool for measuring the mechanical properties of single cells. In particular, providing a capability to manipulate cells in a three-dimensional (3D) space benefits enhancing the applications of AFM measurements in cell biology. Here, we present the complementary integration of AFM and micropipette micromanipulation, which allows precise 3D manipulations and nanomechanical measurements of single living cells. A micropipette micromanipulation system under the guidance of optical microscopy was established to isolate single living cells, and polydimethylsiloxane (PDMS) micropillar substrates were used to physically immobilize the isolated living cells for downstream AFM detection. The viscoelastic properties (Young's modulus, relaxation time, viscosity) of cells were quantitatively measured by AFM-based indentation assay. The effectiveness of micropipette-assisted AFM in single-cell analysis was confirmed on both living animal suspended cells and living animal adherent cells, showing dramatic changes in cell mechanics in different states and revealing the dynamics of single cells grown on micropillar arrays. The study demonstrates the great potential of a micropipette to aid AFM in single-cell manipulations for better accessing the mechanical cues involved in cellular processes, which will allow additional studies of single-cell mechanics and will benefit the field of mechanobiology.