This study proposes a novel strategy for cross-scale position of robotic micromanipulation. The strategy utilizes multiple-scale augmented reality (AR) markers for locating the robotic manipulator on different scales. The macro-marker (3.0 cm-per side, 5 mm×5 mm each square) is applied to position the robot to the microscopic manipulation area. The micro-marker (2.4 mm-per side, 400 μm×400 μm each square) is used for positioning the end-effector under microscopic view. After the fabrication of the markers, the camera's internal parameter matrix was first calibrated. Subsequently, we conducted the detection effect of macro- and micro-markers. Since the observation effect of micro-markers is different under the microscope, the detection distance of the micro-marker was corrected and compensated, and the fixed reference marker was introduced for the correction in different focus heights. Finally, based on detection markers, a robotic manipulator, integrated with a microfluidic chip as an end-effector, was employed to demonstrate the micromanipulation of loading oocytes. The proposed strategy has a potential application in the biology laboratory automation.

This study proposes a novel movable microfluidic chip in which a microfluidic chip is integrated into a robotic manipulator for manipulating oocytes. The microfluidic device has the ability to release a single oocyte with a gap effect. The robotic manipulator can control the position of the microfluidic chip. The microfluidic chip with a pipette tip is directly fabricated using 3D printing. Xenopus oocyte was used in the experiment. When oocytes move from the back side of the channel to the front side, they generate gaps between each other. The gap distance can reach about 16 times the diameter of the oocyte. In addition, a capacitive sensor was used to detect oocytes in the manipulation processes. The results showed that oocytes were successfully released one by one with no deformation in shape using the movable microfluidic chip. The method has significant advantages in biomedicine engineering and micro-nano-manipulation.

This paper presented the three-dimensional oocyte manipulation system for the two-electrode voltage clamp (TEVC) experiment under stereomicroscopy. We firstly developed a sequential calibration method to correlate the workspace of the stereomicroscopy with the image and the micromanipulator. Even though the focal depth of the microscopy was limited, the proposed method functioned the three-dimensional position detection and calculated the homogeneous transformation matrix. We secondly employed hybrid use of the image-based manipulation and the quartz crystal resonator (QCR) force sensor. The imaging technique was used to detect the tip of the glass capillary and the contact to the cell membrane, whereas the QCR force sensor was incorporated to detect the force interaction between the sample and the glass capillary. Using the system and proposed technique, we demonstrated the automatic capillary insertion for TEVC experiment, at which the low insertion depth was preferable. The results indicated that the coordination calibration technique provided the positioning accuracy of the capillary tip on the order of 10 μm. The imaging technique could detect the contact to the elastic objects and cell membrane. QCR force sensor achieved quite small force measurement and feedback control at the control frequency of 100 Hz without latency.

This paper presents a system that picks up protoplasts produced by removing the surrounding cell wall of root cells while preserving their positional information. The fundamental concept of this system involves scanning the root tip over time using a confocal microscopy to measure the positional information of each cell. Then, the protoplast pickup is conducted after switching to a brightfield microscopy to ensure the certainty of pickup. The system measures the position of single protoplasts, adjusts the position of the pipette using a 3-axis micromanipulator, and picks up the target protoplast using a microfluidic pump driven by a piezoelectric actuator. To automate this pickup process, we achieved calibration of the system. The fully automatic 3D calibration of the pipette tip was achieved, allowing 3D micromanipulation under the microscope with an accuracy of 3.1 μm in the XY-plane. Furthermore, by implementing multiple functions such as automatic detection of protoplasts, the process of protoplast pickup has been achieved.