The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Yuzhang Wei - One of the best experts on this subject based on the ideXlab platform.
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design and testing of a new force sensing cell Microinjector based on small stiffness compliant mechanism
IEEE-ASME Transactions on Mechatronics, 2020Co-Authors: Yuzhang WeiAbstract:Cell microinjection is extremely crucial in biomedical domain. In this paper, a new force-sensing cell Microinjector with novel compliant small-stiffness mechanism is proposed. It enables both a high sensing sensitivity and large loading capability. The small-stiffness mechanism is realized by combining a constant-force mechanism and a small positive-stiffness mechanism with force intercept. The small positive-stiffness mechanism is adapted from the constant-force mechanism. The constant-force mechanism is used to eliminate the force intercept of the small positive-stiffness mechanism when the constant-force mechanism works at constant-force motion range. The constant-force mechanism is modeled, simulated, optimized, fabricated, and calibrated. Results show that the designed small-stiffness mechanism can remove the intercept force well. Based on the proposed mechanism, a force-sensing Microinjector is designed and fabricated. Experimental results demonstrate the feasibility of the concept design of the new Microinjector. Moreover, the Microinjector is equipped with force sensing ability by bonding two piezoresistive strain gauges, which provides 2σ resolution of 1.24 mN.
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design and testing of a new cell Microinjector based on small stiffness mechanism
Robotics and Biomimetics, 2019Co-Authors: Yuzhang WeiAbstract:Cell microinjection is extremely crucial in biomedical domain. Currently, cell miciroinjection is mostly operated by manual method and position-based robotic method. However, the success rate and survival rate of the injected cells are relatively low. Force-assisted robotic cell microinjection can provide force feedback and protect the cells from excessive force. In this paper, a new cell Microinjector with novel small-stiffness mechanism is proposed. The small-stiffness property is achieved by combining together a constant-force mechanism and small-stiffness mechanism with force intercept. The constant-force mechanism is used to offset the force intercept of the small-stiffness mechanism when the constant-force mechanism works at constant-force range. The constant-force mechanism is modeled, simulated, optimized, fabricated and calibrated. Results show that the designed constant-force mechanism can offset the intercept force well, because the variation of constant-force value is under 0.1 N during more than 1 mm constant-force motion range. The combined low-stiffness mechanism (without force intercept) can serve as an extremely sensitive force sensor for cell microinjection application.
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design and testing of a new cell Microinjector with embedded soft force sensor
International Conference on Robotics and Automation, 2019Co-Authors: Yuzhang WeiAbstract:Cell microinjection plays an important role in genetics, transgenics, and other biomedical fields. As compared with manual cell microinjection and position-based robotic cell microinjection, force-assisted robotic cell microinjection can improve the success rate and survival rate of the injected cells. In this paper, a novel force-sensing cell injector is designed with piezoresistive force sensor embedded in soft materials. The soft sensors act as fixed-guided beams, which are introduced to achieve the force measurement with high sensitivity in pure one-degree-of-freedom (1-DOF) direction. The injector is developed by considering the installation and replacement issues of the micropipette as well as the connection convenience between the micropipette and tube of compressed air. A prototype of the cell injector with the force sensor is fabricated. Experimental study is conducted to verify its performance in practice.
Ken Chen - One of the best experts on this subject based on the ideXlab platform.
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Analyses of the cell mechanical damage during microinjection
Soft Matter, 2015Co-Authors: Dan Wu, Xiaoyong Wu, Ken ChenAbstract:The microinjection is an essential technique to introduce foreign materials into biological cells. The soft cell is inevitably ruptured by the Microinjector during microinjection. We discuss the way to reduce the mechanical damage by analyzing the control parameters during microinjection. The computational model is developed with the dissipative particle dynamics to simulate the soft mechanical properties of biological cells. The cell model contains the membrane networks, the internal cytoskeleton, crosslink proteins, motors and their functions. The weak power law rheology verifies our computational model. The number of ruptured bonds is used to describe the extent of the mechanical damage that the cell experiences during microinjection. Some experiments are conducted on the Zebrafish embryos. Both the simulation works and experimental results show that the size, shape of the Microinjector tip, and the injection velocity have a significant influence on the cell damage. A small, sharp Microinjector with a high velocity can reduce the mechanical damage.
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A zebrafish embryo behaves both as a "cortical shell-liquid core" structure and a homogeneous solid when experiencing mechanical forces.
Microscopy and microanalysis : the official journal of Microscopy Society of America Microbeam Analysis Society Microscopical Society of Canada, 2014Co-Authors: Fei Liu, Ken ChenAbstract:Mechanical properties are vital for living cells, and various models have been developed to study the mechanical behavior of cells. However, there is debate regarding whether a cell behaves more similarly to a "cortical shell-liquid core" structure (membrane-like) or a homogeneous solid (cytoskeleton-like) when experiencing stress by mechanical forces. Unlike most experimental methods, which concern the small-strain deformation of a cell, we focused on the mechanical behavior of a cell undergoing small to large strain by conducting microinjection experiments on zebrafish embryo cells. The power law with order of 1.5 between the injection force and the injection distance indicates that the cell behaves as a homogenous solid at small-strain deformation. The linear relation between the rupture force and the Microinjector radius suggests that the embryo behaves as membrane-like when subjected to large-strain deformation. We also discuss the possible reasons causing the debate by analyzing the mechanical properties of F-actin filaments.
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Mechanical behavior of cells in microinjection: a minimum potential energy study.
Journal of the mechanical behavior of biomedical materials, 2013Co-Authors: Fei Liu, Ken ChenAbstract:Microinjection is a widely used technique to deliver foreign materials into biological cells. We propose a mathematical model to study the mechanical behavior of a cell in microinjection. Firstly, a cell is modeled by a hyperelastic membrane and interior cytoplasm. Then, based on the fact that the equilibrium configuration of a cell would minimize the potential energy, the energy function during microinjection is analyzed. With Lagrange multiplier and Rayleigh-Ritz technique, we successfully minimize the potential energy and obtain the equilibrium configuration. Upon this model, the injection force, the injection distance, the radius of the Microinjector and the membrane stress are studied. The analysis demonstrates that the Microinjector radius has a significant influence on the cell mechanical behavior: (1) the larger radius generates larger injection force and larger interior pressure at the same injection distance; (2) the radius determines the place where the membrane is most likely to rupture by governing the membrane stress distribution. For a fine Microinjector with radius less than 20% of the cell radius, the most likely rupture point located at the edge of the contact area between the Microinjector and the membrane; however, it may move to the middle of the equilibrium configuration as the radius increases. To verify our model, some experiments were conducted on zebrafish egg cells. The results show that the computational analysis agrees with the experimental data, which supports the findings from the theoretical model.
Miguel A. Cabrerizo-vílchez - One of the best experts on this subject based on the ideXlab platform.
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PRIORITY COMMUNICATION Development of a Constant Surface Pressure Penetration Langmuir Balance Based on Axisymmetric Drop Shape Analysis
2008Co-Authors: H. A. Wege, Juan A. Holgado-terriza, Miguel A. Cabrerizo-vílchezAbstract:A new constant pressure pendant-drop penetration surface balance has been developed combining a pendant-drop surface balance, a rapid-subphase-exchange technique, and a fuzzy logic control algorithm. Beside the determination of insoluble monolayer compression–expansion isotherms, it allows performance of noninvasive kinetic studies of the adsorption of surfactants added to the new subphase onto the free surface and of the adsorption/penetration/reaction of the former onto/into/with surface layers, respectively. The interfacial pressure π is a fundamental parameter in these studies: by working at constant π one controls the height of the energy barrier to adsorption/penetration and can select different regimes and steps of the adsorption/penetration process. In our device a solution drop is formed at the tip of a coaxial double capillary, connected to a double Microinjector. Drop profiles are extracted from digital drop micrographs and fitted to the equation of capillarity, yielding π, the drop volume V, and the interfacial area A. π is varied changing V (and hence A) with the Microinjector. Control is based on a case-adaptable modulated fuzzy-logic PID algorithm able to maintain constant π (or A) under a wide range of experimental conditions. The drop subphase liquid can be exchanged quantitatively by the coaxial capillaries. The adsorption/penetration/reaction kinetics at constant π are then studied monitoring A(t), i.e., determining the relative area change necessary at each instant to compensate the pressure variation due to the interaction of the surfactant in the subsurface with the surface layer. A fully Windows-integrated program manages the whole setup. Examples of experimental protein adsorption and monolayer penetration kinetics are presented. C ○ 2002 Elsevier Science (USA) Key Words: pendant drop; surface balance; monolayer; penetration
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Development of a Constant Surface Pressure Penetration Langmuir Balance Based on Axisymmetric Drop Shape Analysis
Journal of colloid and interface science, 2002Co-Authors: H. A. Wege, Juan A. Holgado-terriza, Miguel A. Cabrerizo-vílchezAbstract:A new constant pressure pendant-drop penetration surface balance has been developed combining a pendant-drop surface balance, a rapid-subphase-exchange technique, and a fuzzy logic control algorithm. Beside the determination of insoluble monolayer compression-expansion isotherms, it allows performance of noninvasive kinetic studies of the adsorption of surfactants added to the new subphase onto the free surface and of the adsorption/penetration/reaction of the former onto/into/with surface layers, respectively. The interfacial pressure pi is a fundamental parameter in these studies: by working at constant pi one controls the height of the energy barrier to adsorption/penetration and can select different regimes and steps of the adsorption/penetration process. In our device a solution drop is formed at the tip of a coaxial double capillary, connected to a double Microinjector. Drop profiles are extracted from digital drop micrographs and fitted to the equation of capillarity, yielding pi, the drop volume V, and the interfacial area A. pi is varied changing V (and hence A) with the Microinjector. Control is based on a case-adaptable modulated fuzzy-logic PID algorithm able to maintain constant pi (or A) under a wide range of experimental conditions. The drop subphase liquid can be exchanged quantitatively by the coaxial capillaries. The adsorption/penetration/reaction kinetics at constant pi are then studied monitoring A(t), i.e., determining the relative area change necessary at each instant to compensate the pressure variation due to the interaction of the surfactant in the subsurface with the surface layer. A fully Windows-integrated program manages the whole setup. Examples of experimental protein adsorption and monolayer penetration kinetics are presented.
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Development of a new Langmuir-type pendant-drop film balance
Colloids and Surfaces B: Biointerfaces, 1999Co-Authors: H. A. Wege, Juan A. Holgado-terriza, M. J. Gálvez-ruiz, Miguel A. Cabrerizo-vílchezAbstract:Abstract A new Langmuir-type pendant-drop film balance has been developed for the determination of surface pressure–molecular area isotherms of insoluble monolayers deposited on the surface of a pendant-drop . The determination of surface tension as a function of surface area is performed using the Axisymmetric Drop Shape Analysis (ADSA). The complete setup, i.e. the image capturing and Microinjector system is fully computer controlled by a user-friendly and fully Windows-integrated program, including the ADSA surface tension calculation algorithm. Two monolayer deposition methods were studied, deposition on capillary and deposition on drop. The latter was found to be more successful. The compression isotherms obtained on monolayers of four amphiphilic substances with different behavior were found to be reproducible and in agreement with conventional film balance isotherms found in literature.
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Axisymmetric drop shape analysis as penetration Langmuir balance
Review of Scientific Instruments, 1999Co-Authors: Miguel A. Cabrerizo-vílchez, H. A. Wege, Juan A. Holgado-terriza, A. W. NeumannAbstract:A new Langmuir-type pendant-drop penetration film balance has been developed combining a Langmuir-type pendant-drop film balance with a new rapid-subphase-exchange technique. In addition to the determination of surface pressure—molecular area isotherms of insoluble monolayers deposited on the surface of a pendant drop, it allows the study of reactions with some surfactant added to the subphase. The monolayer is spread on the surface of a drop suspended from a capillary, which is the outer one of an arrangement of two coaxial capillaries connected to the different branches of a Microinjector. Once the film is brought to the desired state of compression by varying the drop volume with the Microinjector, the subphase liquid in the drop can be exchanged quantitatively by means of the coaxial capillaries. This exchange is complete for a through-flow of at least three times the drop volume, and the monolayers endure it at all tested film pressures. The determination of surface tension as a function of surface area is performed using axisymmetric drop shape analysis (ADSA). The complete set-up, i.e., the image capturing and Microinjector system is fully computer controlled by a user-friendly and fully Windows integrated program, including the ADSA surface tension calculus algorithm. As a penetration film balance, pendant-drop methodologies offer a wide range of advantages such as a more stringent control of the environmental conditions and therefore, more uniform temperature, pressure and concentration along the interface, small amounts of material needed, and a 20 times greater interface/volume ratio than in conventional Langmuir toughs.
De-li Shi - One of the best experts on this subject based on the ideXlab platform.
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Transplantation of Zebrafish Cells by Conventional Pneumatic Microinjector.
Zebrafish, 2017Co-Authors: Ming Shao, Xiao-ning Cheng, Yuan-yuan Liu, De-li ShiAbstract:Generating chimeric zebrafish by transplantation is extremely useful for live imaging in developmental, stem cell, and cancer biology, and to answer the questions of how cells acquire, keep, and/or change their fate. However, as it is technically challenging, the use of transplantation approach remains very limited by the zebrafish community. In this study, we show that this cell grafting operation can be easily achieved by using a conventional pneumatic Microinjector normally used for microinjections. Compared with previously published protocols, which need additional transplantation apparatus, this alternative transplantation method works well, but needs a simpler experimental setup, and is more accessible to all investigators.
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transplantation of zebrafish cells by conventional pneumatic Microinjector
Zebrafish, 2017Co-Authors: Ming Shao, Xiao-ning Cheng, Yuan-yuan Liu, De-li ShiAbstract:Abstract Generating chimeric zebrafish by transplantation is extremely useful for live imaging in developmental, stem cell, and cancer biology, and to answer the questions of how cells acquire, kee...
H. A. Wege - One of the best experts on this subject based on the ideXlab platform.
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PRIORITY COMMUNICATION Development of a Constant Surface Pressure Penetration Langmuir Balance Based on Axisymmetric Drop Shape Analysis
2008Co-Authors: H. A. Wege, Juan A. Holgado-terriza, Miguel A. Cabrerizo-vílchezAbstract:A new constant pressure pendant-drop penetration surface balance has been developed combining a pendant-drop surface balance, a rapid-subphase-exchange technique, and a fuzzy logic control algorithm. Beside the determination of insoluble monolayer compression–expansion isotherms, it allows performance of noninvasive kinetic studies of the adsorption of surfactants added to the new subphase onto the free surface and of the adsorption/penetration/reaction of the former onto/into/with surface layers, respectively. The interfacial pressure π is a fundamental parameter in these studies: by working at constant π one controls the height of the energy barrier to adsorption/penetration and can select different regimes and steps of the adsorption/penetration process. In our device a solution drop is formed at the tip of a coaxial double capillary, connected to a double Microinjector. Drop profiles are extracted from digital drop micrographs and fitted to the equation of capillarity, yielding π, the drop volume V, and the interfacial area A. π is varied changing V (and hence A) with the Microinjector. Control is based on a case-adaptable modulated fuzzy-logic PID algorithm able to maintain constant π (or A) under a wide range of experimental conditions. The drop subphase liquid can be exchanged quantitatively by the coaxial capillaries. The adsorption/penetration/reaction kinetics at constant π are then studied monitoring A(t), i.e., determining the relative area change necessary at each instant to compensate the pressure variation due to the interaction of the surfactant in the subsurface with the surface layer. A fully Windows-integrated program manages the whole setup. Examples of experimental protein adsorption and monolayer penetration kinetics are presented. C ○ 2002 Elsevier Science (USA) Key Words: pendant drop; surface balance; monolayer; penetration
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Development of a Constant Surface Pressure Penetration Langmuir Balance Based on Axisymmetric Drop Shape Analysis
Journal of colloid and interface science, 2002Co-Authors: H. A. Wege, Juan A. Holgado-terriza, Miguel A. Cabrerizo-vílchezAbstract:A new constant pressure pendant-drop penetration surface balance has been developed combining a pendant-drop surface balance, a rapid-subphase-exchange technique, and a fuzzy logic control algorithm. Beside the determination of insoluble monolayer compression-expansion isotherms, it allows performance of noninvasive kinetic studies of the adsorption of surfactants added to the new subphase onto the free surface and of the adsorption/penetration/reaction of the former onto/into/with surface layers, respectively. The interfacial pressure pi is a fundamental parameter in these studies: by working at constant pi one controls the height of the energy barrier to adsorption/penetration and can select different regimes and steps of the adsorption/penetration process. In our device a solution drop is formed at the tip of a coaxial double capillary, connected to a double Microinjector. Drop profiles are extracted from digital drop micrographs and fitted to the equation of capillarity, yielding pi, the drop volume V, and the interfacial area A. pi is varied changing V (and hence A) with the Microinjector. Control is based on a case-adaptable modulated fuzzy-logic PID algorithm able to maintain constant pi (or A) under a wide range of experimental conditions. The drop subphase liquid can be exchanged quantitatively by the coaxial capillaries. The adsorption/penetration/reaction kinetics at constant pi are then studied monitoring A(t), i.e., determining the relative area change necessary at each instant to compensate the pressure variation due to the interaction of the surfactant in the subsurface with the surface layer. A fully Windows-integrated program manages the whole setup. Examples of experimental protein adsorption and monolayer penetration kinetics are presented.
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PRIORITY COMMUNICATION Development of a Constant Surface Pressure Penetration Langmuir Balance Based on Axisymmetric Drop Shape Analysis
2002Co-Authors: H. A. Wege, Juan A. Holgado-terriza, M. A. Cabrerizo-v ´ IlchezAbstract:A new constant pressure pendant-drop penetration surface balance has been developed combining a pendant-drop surface balance, a rapid-subphase-exchange technique, and a fuzzy logic control algorithm. Beside the determination of insoluble monolayer compression‐expansion isotherms, it allows performance of noninvasive kinetic studies of the adsorption of surfactants added to the new subphase onto the free surface and of the adsorption/penetration/reaction of the former onto/into/with surface layers, respectively. The interfacial pressure π is a fundamental parameter in these studies: by working at constant π one controls the height of the energy barrier to adsorption/penetration and can select different regimes and steps of the adsorption/penetration process. In our device a solution drop is formed at the tip of a coaxial double capillary, connected to a double Microinjector. Drop profiles are extracted from digital drop micrographs and fitted to the equation of capillarity, yielding π, the drop volume V, and the interfacial area A. π is varied changing V (and hence A) with the Microinjector. Control is based on a case-adaptable modulated fuzzy-logic PID algorithm able to maintain constant π (or A) under a wide range of experimental conditions. The drop subphase liquid can be exchanged quantitatively by the coaxial capillaries. The adsorption/penetration/reaction kinetics at constant π are then studied monitoring A(t), i.e., determining the relative area change necessary at each instant to compensate the pressure variation due to the interaction of the surfactant in the subsurface with the surface layer. A fully Windows-integrated program manages the whole setup. Examples of experimental protein adsorption and monolayer penetration kinetics are presented. C � 2002 Elsevier Science (USA)
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Development of a new Langmuir-type pendant-drop film balance
Colloids and Surfaces B: Biointerfaces, 1999Co-Authors: H. A. Wege, Juan A. Holgado-terriza, M. J. Gálvez-ruiz, Miguel A. Cabrerizo-vílchezAbstract:Abstract A new Langmuir-type pendant-drop film balance has been developed for the determination of surface pressure–molecular area isotherms of insoluble monolayers deposited on the surface of a pendant-drop . The determination of surface tension as a function of surface area is performed using the Axisymmetric Drop Shape Analysis (ADSA). The complete setup, i.e. the image capturing and Microinjector system is fully computer controlled by a user-friendly and fully Windows-integrated program, including the ADSA surface tension calculation algorithm. Two monolayer deposition methods were studied, deposition on capillary and deposition on drop. The latter was found to be more successful. The compression isotherms obtained on monolayers of four amphiphilic substances with different behavior were found to be reproducible and in agreement with conventional film balance isotherms found in literature.
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Axisymmetric drop shape analysis as penetration Langmuir balance
Review of Scientific Instruments, 1999Co-Authors: Miguel A. Cabrerizo-vílchez, H. A. Wege, Juan A. Holgado-terriza, A. W. NeumannAbstract:A new Langmuir-type pendant-drop penetration film balance has been developed combining a Langmuir-type pendant-drop film balance with a new rapid-subphase-exchange technique. In addition to the determination of surface pressure—molecular area isotherms of insoluble monolayers deposited on the surface of a pendant drop, it allows the study of reactions with some surfactant added to the subphase. The monolayer is spread on the surface of a drop suspended from a capillary, which is the outer one of an arrangement of two coaxial capillaries connected to the different branches of a Microinjector. Once the film is brought to the desired state of compression by varying the drop volume with the Microinjector, the subphase liquid in the drop can be exchanged quantitatively by means of the coaxial capillaries. This exchange is complete for a through-flow of at least three times the drop volume, and the monolayers endure it at all tested film pressures. The determination of surface tension as a function of surface area is performed using axisymmetric drop shape analysis (ADSA). The complete set-up, i.e., the image capturing and Microinjector system is fully computer controlled by a user-friendly and fully Windows integrated program, including the ADSA surface tension calculus algorithm. As a penetration film balance, pendant-drop methodologies offer a wide range of advantages such as a more stringent control of the environmental conditions and therefore, more uniform temperature, pressure and concentration along the interface, small amounts of material needed, and a 20 times greater interface/volume ratio than in conventional Langmuir toughs.