The Experts below are selected from a list of 69 Experts worldwide ranked by ideXlab platform
Kenjiro Takemura - One of the best experts on this subject based on the ideXlab platform.
-
Cell Patterning Method on a Clinically Ubiquitous Culture Dish Using Acoustic Pressure Generated From Resonance Vibration of a Disk-Shaped Ultrasonic Transducer
IEEE Transactions on Biomedical Engineering, 2019Co-Authors: Chikahiro Imashiro, Yuta Kurashina, Taiki Kuribara, Makoto Hirano, Kiichiro Totani, Kenjiro TakemuraAbstract:Cell patterning methods have been previously reported for cell culture. However, these methods use inclusions or devices that are not used in general cell culture and that might affect cell functionality. Here, we report a cell patterning method that can be conducted on a general cell culture dish without any inclusions by employing a resonance vibration of a disk-shaped ultrasonic transducer located under the dish. A resonance vibration with a single Nodal Circle patterned C2C12 myoblasts into a circular shape on the dish with 10-min exposure of the vibration with maximum peak-peak amplitude of 10 μmp-p. Furthermore, the relationship between the amplitude distribution of the transducer and the cell density in the patterned sample could be expressed as a linear function, and there was a clear threshold of amplitude for cell adhesion. To evaluate the cell function of the patterned cells, we conducted proliferation and protein assays at 120-h culture after patterning. Our results showed that the cell proliferation rate did not decrease and the expression of cellular proteins was unchanged. Thus, we conclude, this method can successfully pattern cells in the clinically ubiquitous culture dish, while maintaining cell functionality.
-
Efficient Subculture Process for Adherent Cells by Selective Collection Using Cultivation Substrate Vibration
IEEE Transactions on Biomedical Engineering, 2017Co-Authors: Yuta Kurashina, Kenjiro Takemura, Shogo Miyata, James Friend, Jun KomotoriAbstract:Cell detachment and reseeding are typical operations in cell culturing, often using trypsin exposure and pipetting, even though this process is known to damage the cells. Reducing the number of detachment and reseeding steps might consequently improve the overall quality of the culture, but to date this has not been an option. This study proposes the use of resonant vibration in the cell cultivation substrate to selectively release adherent calf chondrocyte cells: Some were released from the substrate and collected while others were left upon the substrate to grow to confluence as a subculture-without requiring reseeding. An out-of-plane vibration mode with a single Nodal Circle was used in the custom culture substrate. At a maximum vibration amplitude of 0.6 μm, 84.9% of the cells adhering to the substrate were released after 3 min exposure, leaving a sufficient number of cells for passage and long-term cell culture, with the greatest cell concentration along the Nodal Circle where the vibration was relatively quiescent. The 72-h proliferation of the unreleased cells was 20% greater in number than cells handled using the traditional method of trypsin-EDTA (0.050%) release, pipette collection, and reseeding. Due to the vibration, it was possible to reduce the trypsin-EDTA used for selective release to only 0.025%, and in doing so the cell number after 72 h of proliferation was 42% greater in number than the traditional technique.
-
Cell manipulation by Nodal Circle resonance vibration of a cell cultivation substrate
2015 IEEE International Ultrasonics Symposium (IUS), 2015Co-Authors: Chikahiro Imashiro, Yuta Kurashina, Kenjiro Takemura, Shogo Miyata, Jun KomotoriAbstract:In this paper, we propose a novel cell culture method to generate an organ without scaffold. The concept of our study is to apply the principle of Chladni's figures in cell manipulation. To confirm this concept, we developed cell cultivation device that can excite resonance vibration of the cell cultivation substrate. After the fabrication of the device, we estimated the resonance frequency and vibration amplitude distribution of our device. Since the fabricated device successfully produced the designed vibration mode, we conducted cell manipulation experiment to confirm our concept. In our experiment, we varied the initial number of cells that were seeded into our device. Cells were manipulated by resonance vibration for 120 min. After the manipulation, we checked cell distribution on the substrate. As a result, cells were successfully manipulated by the resonance vibration when the initial number of cells was appropriate.
Kentaro Nakamura - One of the best experts on this subject based on the ideXlab platform.
-
Design of a junction for a noncontact ultrasonic transportation system
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2014Co-Authors: Ryota Kashima, Daisuke Koyama, Kentaro Nakamura, Soichi Murakami, Mami MatsukawaAbstract:A junction for noncontact ultrasonic transportation paths in which small objects can be manipulated is proposed. The junction consists of a vibrating disc and a reflector. The reflector is installed parallel to the vibrator to generate an acoustic standing wave in the cavity between the vibrating disc and the reflector. The resonance modes of the acoustic field in the disc cavity between the two plates are calculated theoretically. The distributions of the sound pressure amplitude and the acoustic radiation force in air are calculated using finite element analysis. The flexural vibration modes with one Nodal Circle and four Nodal lines at 45.4 kHz and two Nodal Circles and three Nodal lines at 58.1 kHz are used to trap and eject small objects, respectively. The transportation velocity and the thrust force in the radial direction for a polystyrene particle with a diameter of 2 mm and a weight of 0.3 mg are 812 mm/s and 24 μN, respectively. The ejection direction of the trapped object can be controlled by the driving condition of the vibrating disc.
-
Noncontact ultrasonic transportation of small objects in a circular trajectory in air by flexural vibrations of a circular disc
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2010Co-Authors: Daisuke Koyama, Kentaro NakamuraAbstract:We have developed a noncontact ultrasonic technique for transporting small objects with a linear trajectory over long distances using a bending vibrating plate and a reflector. In this paper, noncontact transportation of small particles around a circular trajectory was investigated. A circular aluminum plate with a piezoelectric ring was employed as a vibrating plate. On the basis of finite element analysis (FEA) calculations, the electrodes of the piezoelectric ring were divided into 24 pieces to generate a flexural vibration mode with one Nodal Circle and four Nodal lines at the resonance frequency of 47.8 kHz. A circular plate having the same dimensions as the vibrating plate was installed parallel to the vibrator. It was used as a reflector to generate an acoustic standing wave in the air between the two plates. The acoustic field between the vibrating plate and reflector was calculated by FEA and the distribution of the acoustic radiation force acting on a small rigid particle was calculated to predict the position of the trapped particle. Using a prototype of the vibrating plate, polystyrene particles with diameters of several millimeters could be trapped at regular intervals along the horizontal Nodal line of the standing wave. The sound pressure distribution between the vibrating plate and reflector was measured by a fiber optic probe and the experimental and calculated results showed good agreement. By switching the driving conditions of the divided electrodes in the circumferential direction, the Nodal lines of the vibrating plate could be rotated and the trapped particle could be manipulated with a circular trajectory in air.
-
noncontact ultrasonic particle manipulation in a circular trajectory using a vibrating disc
2010Co-Authors: Daisuke Koyama, Kentaro NakamuraAbstract:Noncontact transportation of small particles around a circular trajectory was investigated. A circular aluminum plate with a piezoelectric ring was employed as a vibrating plate. On the basis of finite element analysis (FEA) calculations, the electrodes of the piezoelectric ring were divided into 24 pieces to generate a flexural vibration mode with one Nodal Circle and four Nodal lines at the resonance frequency of 47.8 kHz. A circular plate having the same dimensions as the vibrating plate was installed parallel to the vibrator. It was used as a reflector to generate an acoustic standing wave in the air between the two plates. The acoustic field between the vibrating plate and reflector was calculated by FEA and the distribution of the acoustic radiation force acting on a small rigid particle was calculated to predict the position of the trapped particle. Using a prototype of the vibrating plate, polystyrene particles with diameters of several millimeters could be trapped at regular intervals along the horizontal Nodal line of the standing wave. By switching the driving conditions of the divided electrodes in the circumferential direction, the Nodal lines of the vibrating plate could be rotated and the trapped particle could be manipulated with a circular trajectory in air.
-
Stability analysis of an acoustically levitated disk
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2003Co-Authors: Junhui Hu, Kentaro Nakamura, Sadayuki UehaAbstract:In this paper, a model is developed for the stability analysis of an acoustically levitated disk on the basis of analyzing eddy acoustic streaming and acoustic viscous stress. In the model, the effect of the acoustic streaming outside the boundary layer that is on the surface of the levitated disk is properly taken into account. Also, the calculation of sound field and acoustic viscous stress is limited to the range that has a dominant effect on the stability. By this method, we obtain a quite accurate solution of the stability coefficient. For the small horizontal shift of a large levitated disk, the model is verified by the good agreement between the experimental and theoretical results. By means of this model and relevant experiments, some factors that affect the stability of the levitated disk are investigated, and useful guidelines for design and application are obtained. It is found that the range from the edge to the outermost Nodal Circle of the disk-shaped vibrator has a large effect on the stability of the levitated disk. To stabilize the levitated disk by acoustic viscous force, the distance between the edge and the outermost Nodal Circle of the vibrator must be larger than a critical value, which is determined by the driving frequency and the sound velocity of the fluid between the levitated disk and the vibrator. When this condition is satisfied, increasing the distance between the edge and the outermost Nodal Circle leads to a decrease in the stability. It is also found that the property of the fluid between the levitated disk and the vibrator has a large effect on the stability. It is easier to stabilize the levitated disk in steam than in air, but more difficult to do so in carbon dioxide and hydrogen. In addition, theoretical results show that increasing the weight per unit area of the levitated object increases the stability for a given vibrator velocity. The distribution of the acoustic viscous stress and the dependence of the stability coefficient and the holding force on the horizontal shift of the levitated disk, which are obtained by this study, also are useful to a better understanding of the stability of the levitated disk.
Jun Komotori - One of the best experts on this subject based on the ideXlab platform.
-
Efficient Subculture Process for Adherent Cells by Selective Collection Using Cultivation Substrate Vibration
IEEE Transactions on Biomedical Engineering, 2017Co-Authors: Yuta Kurashina, Kenjiro Takemura, Shogo Miyata, James Friend, Jun KomotoriAbstract:Cell detachment and reseeding are typical operations in cell culturing, often using trypsin exposure and pipetting, even though this process is known to damage the cells. Reducing the number of detachment and reseeding steps might consequently improve the overall quality of the culture, but to date this has not been an option. This study proposes the use of resonant vibration in the cell cultivation substrate to selectively release adherent calf chondrocyte cells: Some were released from the substrate and collected while others were left upon the substrate to grow to confluence as a subculture-without requiring reseeding. An out-of-plane vibration mode with a single Nodal Circle was used in the custom culture substrate. At a maximum vibration amplitude of 0.6 μm, 84.9% of the cells adhering to the substrate were released after 3 min exposure, leaving a sufficient number of cells for passage and long-term cell culture, with the greatest cell concentration along the Nodal Circle where the vibration was relatively quiescent. The 72-h proliferation of the unreleased cells was 20% greater in number than cells handled using the traditional method of trypsin-EDTA (0.050%) release, pipette collection, and reseeding. Due to the vibration, it was possible to reduce the trypsin-EDTA used for selective release to only 0.025%, and in doing so the cell number after 72 h of proliferation was 42% greater in number than the traditional technique.
-
Cell manipulation by Nodal Circle resonance vibration of a cell cultivation substrate
2015 IEEE International Ultrasonics Symposium (IUS), 2015Co-Authors: Chikahiro Imashiro, Yuta Kurashina, Kenjiro Takemura, Shogo Miyata, Jun KomotoriAbstract:In this paper, we propose a novel cell culture method to generate an organ without scaffold. The concept of our study is to apply the principle of Chladni's figures in cell manipulation. To confirm this concept, we developed cell cultivation device that can excite resonance vibration of the cell cultivation substrate. After the fabrication of the device, we estimated the resonance frequency and vibration amplitude distribution of our device. Since the fabricated device successfully produced the designed vibration mode, we conducted cell manipulation experiment to confirm our concept. In our experiment, we varied the initial number of cells that were seeded into our device. Cells were manipulated by resonance vibration for 120 min. After the manipulation, we checked cell distribution on the substrate. As a result, cells were successfully manipulated by the resonance vibration when the initial number of cells was appropriate.
Yuta Kurashina - One of the best experts on this subject based on the ideXlab platform.
-
Cell Patterning Method on a Clinically Ubiquitous Culture Dish Using Acoustic Pressure Generated From Resonance Vibration of a Disk-Shaped Ultrasonic Transducer
IEEE Transactions on Biomedical Engineering, 2019Co-Authors: Chikahiro Imashiro, Yuta Kurashina, Taiki Kuribara, Makoto Hirano, Kiichiro Totani, Kenjiro TakemuraAbstract:Cell patterning methods have been previously reported for cell culture. However, these methods use inclusions or devices that are not used in general cell culture and that might affect cell functionality. Here, we report a cell patterning method that can be conducted on a general cell culture dish without any inclusions by employing a resonance vibration of a disk-shaped ultrasonic transducer located under the dish. A resonance vibration with a single Nodal Circle patterned C2C12 myoblasts into a circular shape on the dish with 10-min exposure of the vibration with maximum peak-peak amplitude of 10 μmp-p. Furthermore, the relationship between the amplitude distribution of the transducer and the cell density in the patterned sample could be expressed as a linear function, and there was a clear threshold of amplitude for cell adhesion. To evaluate the cell function of the patterned cells, we conducted proliferation and protein assays at 120-h culture after patterning. Our results showed that the cell proliferation rate did not decrease and the expression of cellular proteins was unchanged. Thus, we conclude, this method can successfully pattern cells in the clinically ubiquitous culture dish, while maintaining cell functionality.
-
Efficient Subculture Process for Adherent Cells by Selective Collection Using Cultivation Substrate Vibration
IEEE Transactions on Biomedical Engineering, 2017Co-Authors: Yuta Kurashina, Kenjiro Takemura, Shogo Miyata, James Friend, Jun KomotoriAbstract:Cell detachment and reseeding are typical operations in cell culturing, often using trypsin exposure and pipetting, even though this process is known to damage the cells. Reducing the number of detachment and reseeding steps might consequently improve the overall quality of the culture, but to date this has not been an option. This study proposes the use of resonant vibration in the cell cultivation substrate to selectively release adherent calf chondrocyte cells: Some were released from the substrate and collected while others were left upon the substrate to grow to confluence as a subculture-without requiring reseeding. An out-of-plane vibration mode with a single Nodal Circle was used in the custom culture substrate. At a maximum vibration amplitude of 0.6 μm, 84.9% of the cells adhering to the substrate were released after 3 min exposure, leaving a sufficient number of cells for passage and long-term cell culture, with the greatest cell concentration along the Nodal Circle where the vibration was relatively quiescent. The 72-h proliferation of the unreleased cells was 20% greater in number than cells handled using the traditional method of trypsin-EDTA (0.050%) release, pipette collection, and reseeding. Due to the vibration, it was possible to reduce the trypsin-EDTA used for selective release to only 0.025%, and in doing so the cell number after 72 h of proliferation was 42% greater in number than the traditional technique.
-
Cell manipulation by Nodal Circle resonance vibration of a cell cultivation substrate
2015 IEEE International Ultrasonics Symposium (IUS), 2015Co-Authors: Chikahiro Imashiro, Yuta Kurashina, Kenjiro Takemura, Shogo Miyata, Jun KomotoriAbstract:In this paper, we propose a novel cell culture method to generate an organ without scaffold. The concept of our study is to apply the principle of Chladni's figures in cell manipulation. To confirm this concept, we developed cell cultivation device that can excite resonance vibration of the cell cultivation substrate. After the fabrication of the device, we estimated the resonance frequency and vibration amplitude distribution of our device. Since the fabricated device successfully produced the designed vibration mode, we conducted cell manipulation experiment to confirm our concept. In our experiment, we varied the initial number of cells that were seeded into our device. Cells were manipulated by resonance vibration for 120 min. After the manipulation, we checked cell distribution on the substrate. As a result, cells were successfully manipulated by the resonance vibration when the initial number of cells was appropriate.
Daisuke Koyama - One of the best experts on this subject based on the ideXlab platform.
-
Design of a junction for a noncontact ultrasonic transportation system
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2014Co-Authors: Ryota Kashima, Daisuke Koyama, Kentaro Nakamura, Soichi Murakami, Mami MatsukawaAbstract:A junction for noncontact ultrasonic transportation paths in which small objects can be manipulated is proposed. The junction consists of a vibrating disc and a reflector. The reflector is installed parallel to the vibrator to generate an acoustic standing wave in the cavity between the vibrating disc and the reflector. The resonance modes of the acoustic field in the disc cavity between the two plates are calculated theoretically. The distributions of the sound pressure amplitude and the acoustic radiation force in air are calculated using finite element analysis. The flexural vibration modes with one Nodal Circle and four Nodal lines at 45.4 kHz and two Nodal Circles and three Nodal lines at 58.1 kHz are used to trap and eject small objects, respectively. The transportation velocity and the thrust force in the radial direction for a polystyrene particle with a diameter of 2 mm and a weight of 0.3 mg are 812 mm/s and 24 μN, respectively. The ejection direction of the trapped object can be controlled by the driving condition of the vibrating disc.
-
noncontact ultrasonic particle manipulation in a circular trajectory using a vibrating disc
2010Co-Authors: Daisuke Koyama, Kentaro NakamuraAbstract:Noncontact transportation of small particles around a circular trajectory was investigated. A circular aluminum plate with a piezoelectric ring was employed as a vibrating plate. On the basis of finite element analysis (FEA) calculations, the electrodes of the piezoelectric ring were divided into 24 pieces to generate a flexural vibration mode with one Nodal Circle and four Nodal lines at the resonance frequency of 47.8 kHz. A circular plate having the same dimensions as the vibrating plate was installed parallel to the vibrator. It was used as a reflector to generate an acoustic standing wave in the air between the two plates. The acoustic field between the vibrating plate and reflector was calculated by FEA and the distribution of the acoustic radiation force acting on a small rigid particle was calculated to predict the position of the trapped particle. Using a prototype of the vibrating plate, polystyrene particles with diameters of several millimeters could be trapped at regular intervals along the horizontal Nodal line of the standing wave. By switching the driving conditions of the divided electrodes in the circumferential direction, the Nodal lines of the vibrating plate could be rotated and the trapped particle could be manipulated with a circular trajectory in air.
-
Noncontact ultrasonic transportation of small objects in a circular trajectory in air by flexural vibrations of a circular disc
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2010Co-Authors: Daisuke Koyama, Kentaro NakamuraAbstract:We have developed a noncontact ultrasonic technique for transporting small objects with a linear trajectory over long distances using a bending vibrating plate and a reflector. In this paper, noncontact transportation of small particles around a circular trajectory was investigated. A circular aluminum plate with a piezoelectric ring was employed as a vibrating plate. On the basis of finite element analysis (FEA) calculations, the electrodes of the piezoelectric ring were divided into 24 pieces to generate a flexural vibration mode with one Nodal Circle and four Nodal lines at the resonance frequency of 47.8 kHz. A circular plate having the same dimensions as the vibrating plate was installed parallel to the vibrator. It was used as a reflector to generate an acoustic standing wave in the air between the two plates. The acoustic field between the vibrating plate and reflector was calculated by FEA and the distribution of the acoustic radiation force acting on a small rigid particle was calculated to predict the position of the trapped particle. Using a prototype of the vibrating plate, polystyrene particles with diameters of several millimeters could be trapped at regular intervals along the horizontal Nodal line of the standing wave. The sound pressure distribution between the vibrating plate and reflector was measured by a fiber optic probe and the experimental and calculated results showed good agreement. By switching the driving conditions of the divided electrodes in the circumferential direction, the Nodal lines of the vibrating plate could be rotated and the trapped particle could be manipulated with a circular trajectory in air.