Cell scratching device

Abstract

The invention provides a cell scratching device. The cell scratching device comprises a magnetic driving turntable, a composite bracket, a mechanical arm and a control system, a honeycomb-shaped electromagnetic array is embedded in the magnetic driving turntable and is dynamically adsorbed with a ferromagnetic layer at the bottom of the porous plate, so that accurate positioning is realized; the composite bracket is integrated with a pneumatic telescopic positioning rod and a composite positioning module, so that the scratch stability is ensured, and the cell state is monitored in real time; the tail end of the mechanical arm is connected with a dynamic balance actuator and is assembled with a flat straight shovel-shaped needle head, so that high-precision scratching operation is realized; the control system coordinates all the parts to work through a multi-stage control module, and has the functions of automatic scratching, real-time monitoring and feedback control.

Description

Technical Field

[0001] The invention relates to the fields of biomedicine and tissue engineering, and in particular to a cell scratching device. Background Art

[0002] In biomedical research, the scratch test is a commonly used method for studying cell migration and wound healing. Traditional scratch tests are usually performed manually, which has disadvantages such as uneven scratches, uncontrollable depth, and inability to monitor in real time. In recent years, with the development of automation technology and precision manufacturing technology, a variety of automatic scratch devices have emerged, but these devices still have some shortcomings, such as insufficient scratch accuracy, inability to adapt to multi-well plates of different specifications, and lack of real-time monitoring and feedback control functions. Therefore, the development of a high-precision, intelligent scratch device is of great practical significance. Summary of the invention

[0003] The purpose of the present invention is to provide a high-precision, intelligent scratching device, which can realize accurate scratching operations on biological samples such as cells and has real-time monitoring and control functions to solve the shortcomings of the prior art.

[0004] The present invention is a scratching device, comprising: The magnetic drive turntable has a honeycomb electromagnetic array embedded on its surface, which forms a dynamic adsorption with the ferromagnetic layer at the bottom of the porous plate. An equally divided scale ring and a grating sensor are set on the edge to output the turntable angle signal in real time. The composite bracket has an integrated pneumatic telescopic positioning rod in the vertical part of the bracket, which cooperates with the positioning hole of the turntable in an air pressure seal. The horizontal part is provided with a composite positioning module, which includes a coaxial industrial camera and a microscope objective lens to collect bright field images and a laser Doppler vibrometer to generate a vibration velocity map. The end of the robot arm is connected to a dynamic balance actuator through a ball-jointed flexible joint. The actuator has a built-in dual piezoelectric chip driver and a six-dimensional force sensor, and the output end is equipped with a replaceable flat straight spade-shaped needle. The flat straight spade-shaped needle has a 30° acute angle at the front of the blade, a 15° wedge-shaped reinforcement portion in the middle, and a bionic microgroove on the surface. The groove depth h and the blade thickness u satisfy h=0.2u±0.05u, where h is in μm and u is in μm.

[0005] Preferably, the honeycomb electromagnetic array is composed of 128 independent electromagnetic units, each unit is arranged in a regular hexagon with a side length of 5.17 mm or 2.83 mm; Each unit is equipped with a PID temperature control module, the operating temperature is maintained at 25±0.5℃, and the temperature control accuracy is ±0.1℃; The spacing between adjacent electromagnetic units is 1 / 3 of the center distance of a single hole of the multi-hole plate to be tested. The multi-hole plate is a 6-hole plate or a 12-hole plate, and the center distance of a single hole is 15.5 mm or 8.5 mm, respectively.

[0006] Preferably, the laser Doppler vibrometers are distributed in an equilateral triangle, the side length of the triangle is 0.7 times the diameter of a single hole of the porous plate, and the deviation between the center point of the triangle and the optical axis of the microscope objective is less than 10 μm.

[0007] Preferably, the driving signal of the dual piezoelectric chip driver is a linear frequency sweep waveform modulated by a Hanning window, with a frequency sweep range of 20-30 kHz and a frequency sweep rate of 500 Hz / ms.

[0008] Preferably, the silicone damping layer of the ball-joint flexible joint has a gradient Young's modulus distribution: 5±0.2MPa near the actuator end, 0.5±0.05MPa near the robot arm end; The damping coefficient changes with temperature at a rate of <0.001 / °C, and the operating temperature range is 20-30°C.

[0009] Preferably, the turntable positioning control module is electrically connected to the grating sensor and configured to receive the turntable angle signal and calculate the rotation speed n, according to Dynamically adjust the adsorption force F of the electromagnetic array and transmit the speed n to the trajectory planning module through the CAN bus, where n is in rpm and F is in N; Visual-mechanical detection module: integrated in the composite positioning module, including: image processing unit, which performs Sobel edge detection on the bright field images continuously collected by the industrial camera, extracts the cell density distribution and calculates the cell migration speed; frequency domain analysis unit, which performs Fourier transform on the vibration velocity diagram of the laser Doppler vibrometer to extract the stiffness characteristics; data synchronization unit, which uses FPGA hardware to realize the timestamp alignment of the image and vibration velocity data; Trajectory execution control module: forms a closed loop with the robot arm and the dual piezoelectric chip driver, and is configured as follows: The cell density and stiffness data were fused based on the 3D-Unet neural network to generate a third-order Bezier curve path; The path is converted into the angular velocity command of the robot joint through inverse kinematics solution; Receive the contact force data Fz and the cell migration speed v sent by the six-dimensional force sensor in real time. The unit of Fz is mN and the unit of v is μm / h. The needle angle compensation θc is calculated by the Lyapunov stability controller, ; Where, the unit of θc is rad; dFz / dt is the contact force change rate, in mN / ms; Kp is the proportional gain coefficient, in rad·h / μm; Kd is the differential gain coefficient, in rad·h² / μm; The bimorph actuator is driven to adjust the needle cutting angle.

[0010] Preferably, the input layer of the 3D-Unet convolutional neural network comprises a bright field image branch and a laser velocity map branch connected in parallel; The output layer generates a multi-order Bezier curve path with probability weights.

[0011] Preferably, the sampling frequency of the six-dimensional force sensor is 10kHz, and the Z-axis resolution is 0.1mN; The fast Fourier transform module is configured to extract the frequency domain characteristics of stiffness in the frequency band of 0.1-100 Hz with a frequency resolution of 0.1 Hz.

[0012] Preferably, the six-dimensional force sensor has a sampling frequency of 10kHz and a Z-axis resolution of 0.1mN; Configure the filter and calculate the contact force change rate as follows: , where t is the current time point, in seconds; Δ t is the sampling time interval, the unit is s; Fz is the contact force data, the unit is mN. DETAILED DESCRIPTION

[0013] The scratching device of the present invention comprises the following main components: a magnetically driven turntable is used to fix and drive the porous plate to rotate, thereby realizing precise angle control; a composite bracket is used to support and position the porous plate, thereby ensuring the stability of the scratching operation; a mechanical arm is used to control the movement of the scratching needle, thereby realizing high-precision scratching operation; and a control system is used to coordinate the work of each part, thereby realizing automated scratching operation and real-time monitoring.

[0014] The magnetically driven turntable is one of the key components of the present invention. A honeycomb electromagnetic array is embedded on its surface, forming dynamic adsorption with the ferromagnetic layer at the bottom of the porous plate. The electromagnetic array consists of 128 independent electromagnetic units, each of which is arranged in a regular hexagon with a side length of 5.17mm or 2.83mm. Each electromagnetic unit is equipped with a PID temperature control module, and the operating temperature is maintained at 25±0.5℃, with a temperature control accuracy of ±0.1℃. The spacing between adjacent electromagnetic units is 1 / 3 of the center distance of a single hole of the porous plate to be tested. The porous plate is a 6-hole plate or a 12-hole plate, and the center distance of a single hole is 15.5mm or 8.5mm, respectively.

[0015] The magnetically driven turntable forms dynamic adsorption with the ferromagnetic layer at the bottom of the porous plate through the honeycomb electromagnetic array, achieving precise positioning and stable fixation of the porous plate. The PID temperature control module ensures the stable working temperature of the electromagnetic unit to avoid the influence of temperature changes on the experimental results. The grating sensor outputs the turntable angle signal in real time to provide precise angle control for subsequent scratching operations. The design of the magnetically driven turntable enables the porous plate to remain stable during the scratching process, avoiding scratching errors caused by vibration or displacement. At the same time, the dynamic adsorption function of the electromagnetic array can quickly replace the porous plate as needed, improving experimental efficiency.

[0016] The composite bracket includes a vertical part and a horizontal part. The vertical part integrates a pneumatic telescopic positioning rod, which cooperates with the turntable positioning hole in an air pressure seal to achieve rapid positioning and fixation of the multi-well plate. The horizontal part is provided with a composite positioning module, including a coaxial industrial camera and a microscope objective to collect bright field images and a laser Doppler vibrometer, which generates a vibration velocity diagram. The composite bracket cooperates with the turntable positioning hole through a pneumatic telescopic positioning rod to achieve rapid positioning and fixation of the multi-well plate. The coaxial industrial camera and the microscope objective in the composite positioning module collect bright field images for observing the morphology and distribution of cells. The laser Doppler vibrometer generates a vibration velocity diagram for monitoring the vibration of cells and providing a reference for subsequent scratching operations. The design of the composite bracket enables the multi-well plate to remain stable during the scratching process, avoiding scratching errors caused by vibration or displacement. At the same time, the multimodal detection function of the composite positioning module can monitor the state of cells in real time and provide precise guidance for the scratching operation.

[0017] The end of the robot arm is connected to the dynamic balance actuator through a ball-jointed flexible joint. The actuator has a built-in dual piezoelectric chip driver and a six-dimensional force sensor, and the output end is equipped with a replaceable flat straight spade needle. The front section of the flat straight spade needle blade is a 30° sharp-angle thin layer, and the middle section transitions to a 15° wedge-shaped reinforcement. The surface is provided with bionic micro-grooves, and the groove depth h and the blade thickness t satisfy h=0.2t±0.05t. The robot arm is connected to the dynamic balance actuator through a ball-jointed flexible joint to achieve high-precision motion control. The dual piezoelectric chip driver provides precise driving force, and the six-dimensional force sensor detects the contact force in real time to ensure the stability and accuracy of the scratching operation. The design of the flat straight spade needle makes the scratching operation more precise, and the design of the bionic micro-groove can reduce the resistance during the scratching process and improve the scratching quality.

[0018] The present invention includes a control system, which includes a multi-level control module, and the control relationship between components is constructed in the following order: Turntable positioning control module: electrically connected to the grating sensor, configured to receive the turntable angle signal and calculate the speed n, according to Dynamically adjust the adsorption force of the electromagnetic array and transmit the speed n to the trajectory planning module through the CAN bus, where n is in rpm and F is in N; Visual-mechanical detection module: integrated in the composite positioning module, including: image processing unit, which performs Sobel edge detection on the bright field images continuously collected by the industrial camera, extracts the cell density distribution and calculates the cell migration speed; frequency domain analysis unit, which performs Fourier transform on the vibration velocity diagram of the laser Doppler vibrometer to extract the stiffness characteristics; data synchronization unit, which uses FPGA hardware to realize the timestamp alignment of the image and vibration velocity data; Trajectory execution control module: forms a closed loop with the robot arm and the dual piezoelectric chip driver, and is configured as follows: The cell density and stiffness data were fused based on the 3D-Unet neural network to generate a third-order Bezier curve path; The path is converted into the angular velocity command of the robot joint through inverse kinematics solution; Receive the contact force data Fz and the cell migration speed v sent by the six-dimensional force sensor in real time, where the unit of Fz is mN and the unit of v is μm / h; The needle angle compensation θc is calculated by the Lyapunov stability controller, = +

[0019] in: , , dFz / dt is the contact force change rate, in mN / ms; Kp is the proportional gain coefficient, in rad·h / μm; Kd is the differential gain coefficient, in rad·h² / μm; The bimorph actuator is driven to adjust the needle cutting angle.

[0020] The control system achieves precise control of the scratching device through multi-level control modules. The first-level control module receives the turntable angle signal of the grating sensor, calculates the turntable speed, and dynamically adjusts the adsorption force of the electromagnetic array according to the turntable speed to ensure the stable fixation of the multi-well plate. The second-level control module obtains the bright field image and vibration velocity map through the composite positioning module, extracts the cell density distribution and stiffness characteristics, and provides a reference for the subsequent scratching operation. The third-level control module fuses the bright field image and vibration velocity data based on the 3D-Unet convolutional neural network, generates a multi-order Bezier curve path, converts the path command into the robot arm joint angular velocity command, and drives the robot arm to move. The six-dimensional force sensor detects the contact force in real time, calculates the needle angle compensation through the Lyapunov stability controller, drives the dual piezoelectric chip driver to adjust the needle cutting angle, forms a closed-loop control, and ensures the accuracy and stability of the scratching operation. The multi-level control module design of the control system enables the scratching device to achieve high-precision automatic operation. The real-time monitoring and feedback control functions can ensure the accuracy and consistency of the scratching operation and improve the reliability and repeatability of the experiment.

[0021] During the scratching operation, the porous plate is placed on a magnetically driven turntable, and dynamic adsorption is formed between the electromagnetic array and the ferromagnetic layer at the bottom of the porous plate to achieve precise positioning and stable fixation of the porous plate. The grating sensor outputs the turntable angle signal in real time. The control system calculates the turntable rotation speed according to the signal and dynamically adjusts the adsorption force of the electromagnetic array according to the turntable speed to ensure that the porous plate remains stable during the scratching process. The coaxial industrial camera and microscope objective in the composite positioning module collect bright field images, and the laser Doppler vibrometer generates a vibration velocity diagram. The data is sent to the control system after time stamp alignment. The control system fuses the bright field image and vibration velocity data based on the 3D-Unet convolutional neural network to generate a multi-order Bezier curve path. The path command is converted into a robot arm joint angular velocity command to drive the seven-degree-of-freedom robot arm to move. The six-dimensional force sensor detects the contact force in real time, calculates the needle angle compensation through the Lyapunov stability controller, drives the dual piezoelectric chip driver to adjust the needle cutting angle, and forms a closed-loop control to ensure the accuracy and stability of the scratching operation.

[0022] The entire scratching device achieves high-precision scratching operations on biological samples such as cells through the coordinated work of the magnetically driven turntable, composite bracket, robotic arm and control system. The magnetically driven turntable and composite bracket ensure the stable fixation and precise positioning of the multi-well plate, the robotic arm achieves high-precision scratching operations, and the control system achieves automated scratching operations and real-time monitoring through multi-level control modules to ensure the accuracy and consistency of the scratching operation.

[0023] The scratching device of the present invention realizes high-precision scratching operation on biological samples such as cells through the coordinated work of a magnetically driven turntable, a composite bracket, a mechanical arm and a control system, and has real-time monitoring and control functions. The device has the advantages of simple operation, high precision, strong adaptability, etc., can meet the high requirements of scratch experiments in biomedical research, and has broad application prospects.

Claims

1. A cell scratching device, characterized in that include: The magnetic drive turntable has a honeycomb electromagnetic array embedded on its surface, which forms a dynamic adsorption with the ferromagnetic layer at the bottom of the porous plate. An equally divided scale ring and a grating sensor are set on the edge to output the turntable angle signal in real time. The composite bracket has an integrated pneumatic telescopic positioning rod in the vertical part of the bracket, which cooperates with the positioning hole of the turntable in an air pressure seal. The horizontal part is provided with a composite positioning module, which includes a coaxial industrial camera and a microscope objective lens to collect bright field images and a laser Doppler vibrometer to generate a vibration velocity map. The end of the robot arm is connected to a dynamic balance actuator through a ball-jointed flexible joint. The actuator has a built-in dual piezoelectric chip driver and a six-dimensional force sensor, and the output end is equipped with a replaceable flat straight spade-shaped needle. The flat straight spade-shaped needle has a 30° acute angle at the front of the blade, a 15° wedge-shaped reinforcement portion in the middle, and a bionic microgroove on the surface. The groove depth h and the blade thickness u satisfy h=0.2u±0.05u, where h is in μm and u is in μm.

2. The device according to claim 1, characterized in that: The honeycomb electromagnetic array consists of 128 independent electromagnetic units, each of which is arranged in a regular hexagon with a side length of 5.17mm or 2.83mm; Each unit is equipped with a PID temperature control module, the operating temperature is maintained at 25±0.5℃, and the temperature control accuracy is ±0.1℃; The spacing between adjacent electromagnetic units is 1 / 3 of the center distance of a single hole of the multi-hole plate to be tested. The multi-hole plate is a 6-hole plate or a 12-hole plate, and the center distance of a single hole is 15.5 mm or 8.5 mm, respectively.

3. The device according to claim 1, characterized in that: The laser Doppler vibrometers are distributed in an equilateral triangle, the side length of the triangle is 0.7 times the diameter of a single hole in the porous plate, and the deviation between the center point of the triangle and the optical axis of the microscope objective is less than 10μm.

4. The device according to claim 1, characterized in that: The driving signal of the dual piezoelectric chip driver is a linear frequency sweep waveform modulated by Hanning window, with a sweep range of 20-30kHz and a sweep rate of 500Hz / ms.

5. The device according to claim 1, characterized in that: The silicone damping layer of the ball-joint flexible joint has a gradient Young's modulus distribution: 5±0.2MPa near the actuator end, 0.5±0.05MPa near the robot arm end; The damping coefficient changes with temperature at a rate of <0.001 / °C, and the operating temperature range is 20-30°C.

6. The device according to claim 1, characterized in that Integrate the following control subsystems: Turntable positioning control module: electrically connected to the grating sensor, configured to receive the turntable angle signal and calculate the speed n, according to Dynamically adjust the adsorption force F of the electromagnetic array and transmit the speed n to the trajectory planning module through the CAN bus, where n is in rpm and F is in N; Visual-mechanical detection module: integrated in the composite positioning module, including: image processing unit, which performs Sobel edge detection on the bright field images continuously acquired by the industrial camera, extracts the cell density distribution and calculates the cell migration speed; frequency domain analysis unit, which performs Fourier transform on the vibration velocity map of the laser Doppler vibrometer to extract the stiffness characteristics; The data synchronization unit uses FPGA hardware to achieve the timestamp alignment of image and vibration data; Trajectory execution control module: forms a closed loop with the robot arm and the dual piezoelectric chip driver, and is configured as follows: The cell density and stiffness data were fused based on the 3D-Unet neural network to generate a third-order Bezier curve path; The path is converted into the angular velocity command of the robot joint through inverse kinematics solution; Receive the contact force data Fz and the cell migration speed v sent by the six-dimensional force sensor in real time. The unit of Fz is mN and the unit of v is μm / h. The needle angle compensation θc is calculated by the Lyapunov stability controller, ； Wherein, the unit of θc is rad; dFz / dt is the contact force change rate, in mN / ms; Kp is the proportional gain coefficient, in rad·h / μm; Kd is the differential gain coefficient, in rad·h² / μm; The bimorph actuator is driven to adjust the needle cutting angle.

7. The device according to claim 6, characterized in that: The input layer of the 3D-Unet convolutional neural network contains a bright field image branch and a laser velocity map branch in parallel; The output layer generates a multi-order Bezier curve path with probability weights.

8. The device according to claim 1, characterized in that: The sampling frequency of the six-dimensional force sensor is 10kHz, and the Z-axis resolution is 0.1mN; The fast Fourier transform module is configured to extract the frequency domain characteristics of stiffness in the frequency band of 0.1-100 Hz with a frequency resolution of 0.1 Hz.

9. The device according to claim 1, characterized in that: The six-dimensional force sensor has a sampling frequency of 10kHz and a Z-axis resolution of 0.1mN. A filter is configured and the contact force change rate is calculated using the central difference method: Where t is the current time point, in seconds; Δ t is the sampling time interval, the unit is s; Fz is the contact force data, the unit is mN.

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