scholarly journals A Disposable Pneumatic Microgripper for Cell Manipulation with Image-Based Force Sensing

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 707 ◽  
Author(s):  
Benjamin Gursky ◽  
Sebastian Bütefisch ◽  
Monika Leester-Schädel ◽  
Kangqi Li ◽  
Barbara Matheis ◽  
...  
Keyword(s):  
Cell Damage ◽  
Cost Effective ◽  
Force Sensor ◽  
Cell Manipulation ◽  
Patch Clamp Technique ◽  
Liquid Environment ◽  
Reusable Components ◽  
Electrophysiological Measurements ◽  
Single Use ◽  
Gripping Force

A new design for a single-use disposable pneumatic microgripper is presented in this paper. It enables very cost-effective batch microfabrication in SU-8 with a single lithography mask by shifting manufacturing complexity into reusable components. An optically readable force sensor with potential to be used in a feedback loop has been integrated in order to enable gripping with a controlled force. The sensors are first examined separately from the gripper and exhibit good linearity. The gripper function utilizes the disposable gripper element together with a reusable gripper fixture. During experiments, the pneumatically actuated microgripper can vary the gripping force within a range of a few mN (up to 5.7 mN was observed). This microgripper is planned to be used in a liquid environment for gripping larger aggregates of cells in combination with the patch clamp technique. This approach will allow Langerhans islets suspended in an electrolyte solution to be grasped and held during electrophysiological measurements without cell damage.

scholarly journals Customizable Optical Force Sensor for Fast Prototyping and Cost-Effective Applications

Sensors ◽  
2018 ◽  
Vol 18 (2) ◽  
pp. 493 ◽  
Author(s):  
Jorge Díez ◽  
José Catalán ◽  
Andrea Blanco ◽  
José García-Perez ◽  
Francisco Badesa ◽  
...  
Keyword(s):  
Cost Effective ◽  
Force Sensor ◽  
Optical Force ◽  
Fast Prototyping

The complement membrane attack complex and the bystander effect in cerebral vasospasm

1997 ◽  
Vol 3 (4) ◽  
pp. E7
Author(s):  
Charles C. Park ◽  
Moon L. Shin ◽  
J. Marc Simard
Keyword(s):  
Smooth Muscle ◽  
Cerebral Vasospasm ◽  
Complement Activation ◽  
Bystander Effect ◽  
Cell Damage ◽  
Membrane Attack Complex ◽  
Membrane Conductance ◽  
Autologous Serum ◽  
Innocent Bystander ◽  
Patch Clamp Technique

Activation of complement results in formation of membrane attack complexes (MACs) that can insert themselves either into cells that initiate complement activation or into nearby (“innocent bystander”) cells. The MACs form large-conductance, nonspecific ion channels that can cause lytic or sublytic cell damage. The authors used a highly sensitive patch clamp technique to assess the contribution of the bystander effect to the pathophysiology of cerebral vasospasm. They compared the effect of complement activation by autologous aged versus fresh erythrocytes on the membrane conductance of freshly isolated rat cerebral artery smooth-muscle cells. In the presence of autologous serum, aged, but not fresh, erythrocytes caused a large increase in membrane conductance, an effect that was prevented by heat-inactivating the serum. Ethyleneglycol tetraacetic acid in the presence of Mg++ attenuated the effect, indicating that complement activation was taking place via the classic pathway. The effect was reproduced by zymosan-activated autologous serum, suggesting that such changes in conductance could result from insertion of MACs secondary to a bystander effect. Both C8- and C9-depleted heterologous sera produced minimal effects that were converted to full effect by addition of the missing complement component. Superoxide dismutase plus catalase did not attenuate the conductance changes produced by autologous serum plus aged erythrocytes. Autologous serum plus aged erythrocyte membrane ghosts that were free of lysate caused a typical increase in conductance. This study demonstrates that complement activation by aged erythrocytes can result in MAC insertion into innocent bystander smooth-muscle cell membranes and that this mechanism, heretofore undescribed, may contribute to development of vasospasm after subarachnoid hemorrhage.

scholarly journals Method for the Detection of Tumor Blood Vessels in Neurosurgery Using a Gripping Force Feedback System

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5157
Author(s):  
Hiroki Yokota ◽  
Takeshi Yoneyama ◽  
Tetsuyou Watanabe ◽  
Yasuo Sasagawa ◽  
Mitsutoshi Nakada
Keyword(s):  
Blood Vessel ◽  
Blood Vessels ◽  
Force Feedback ◽  
Correlation Coefficients ◽  
Feedback System ◽  
Force Sensor ◽  
Robot System ◽  
Blood Vessel Detection ◽  
Operating Space ◽  
Gripping Force

Avoiding unnecessary bleeding during neuroendoscopic surgeries is crucial because achieving hemostasis in a narrow operating space is challenging. However, when the location of a blood vessel in a tumor cannot be visually confirmed, unintentional damage to the vessel and subsequent bleeding may occur. This study proposes a method for tumor blood vessel detection using a master–slave surgical robot system equipped with a force sensor in the slave gripper. Using this method, blood pulsation inside a tumor was detected, displayed as a gripping force wave, via the slave force sensor. The characteristics of gripping force due to blood pulsation were extracted by measuring the fluctuation of the force in real time. The presence or absence of blood vessels was determined on the basis of cross-correlation coefficients between the gripping force fluctuation waveform due to blood pulsation and model fluctuation waveform. Experimental validation using two types of simulated tumors (soft: E = 6 kPa; hard: E = 38 kPa) and a simulated blood vessel (E = 1.9 MPa, radius = 0.5 mm, thickness = 0.1 mm) revealed that the presence of blood vessels could be detected while gripping at a constant angle and during transient gripping.

scholarly journals Macrophage Damage by Leishmania amazonensis Cytolysin: Evidence of Pore Formation on Cell Membrane

2000 ◽  
Vol 68 (8) ◽  
pp. 4578-4584 ◽  
Author(s):  
Fátima S. M. Noronha ◽  
Jader S. Cruz ◽  
Paulo S. L. Beirão ◽  
M. Fátima Horta
Keyword(s):  
Cell Membrane ◽  
Patch Clamp ◽  
Pore Formation ◽  
Cell Damage ◽  
Leishmania Amazonensis ◽  
Temperature Dependent ◽  
Patch Clamp Technique ◽  
Protein Subunits ◽  
Target Cell Membrane ◽  
Target Membrane

ABSTRACT We have previously shown that both promastigotes and amastigotes ofLeishmania amazonensis contain a lytic protein that damages erythrocytes and nucleated cells, including macrophages (F. S. M. Noronha, F. J. Ramalho-Pinto, and M. F. Horta, Infect. Immun. 64:3975–3982, 1996). Using the patch-clamp technique, we show here that cell damage by parasite extracts is mediated by the formation of nonselective pores on the target membrane. This demonstrates that L. amazonensis cytolysin is a pore-forming protein (PFP), here named leishporin. We show that the diameters of the pores formed by parasite extracts are heterogeneous, varying from ∼1.6 to >6.1 nm according to cytolysin concentration or time. We also show that pore formation involves the binding of the PFP to the target cell membrane, a temperature-independent event that is necessary but not sufficient to lyse cells. This is followed by a temperature-dependent step that triggers lysis, probably the insertion and the polymerization of protein subunits in the lipid bilayer. We provide evidence that suggests that polymerization of single subunits must occur for pore formation. We show, in addition, that L. amazonensis expresses molecules antigenically homologous to other PFPs.

scholarly journals Sheathless Shape-Based Separation of Candida Albicans Using a Viscoelastic Non-Newtonian Fluid

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 817 ◽  
Author(s):  
Jeonghun Nam ◽  
Hyunseul Jee ◽  
Woong Sik Jang ◽  
Jung Yoon ◽  
Borae G. Park ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Newtonian Fluid ◽  
Separation Efficiency ◽  
Cost Effective ◽  
Cell Manipulation ◽  
Cell Type ◽  
Accurate Identification ◽  
Cost Effective Treatment ◽  
Drug Assays ◽  
Different Shapes

Rapid and accurate identification of Candida albicans from among other candida species is critical for cost-effective treatment and antifungal drug assays. Shape is a critical biomarker indicating cell type, cell cycle, and environmental conditions; however, most microfluidic techniques have been focused only on size-based particle/cell manipulation. This study demonstrates a sheathless shape-based separation of particles/cells using a viscoelastic non-Newtonian fluid. The size of C. albicans was measured at 37 °C depending on the incubation time (0 h, 1 h, and 2 h). The effects of flow rates on the flow patterns of candida cells with different shapes were examined. Finally, 2-h-incubated candida cells with germ tube formations (≥26 μm) were separated from spherical candida cells and shorter candida cells with a separation efficiency of 80.9% and a purity of 91.2% at 50 μL/min.

scholarly journals Characterization of an N-terminal Nav1.5 channel variant – a potential risk factor for arrhythmias and sudden death?

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Stefanie Scheiper-Welling ◽  
Paolo Zuccolini ◽  
Oliver Rauh ◽  
Britt-Maria Beckmann ◽  
Christof Geisen ◽  
...  
Keyword(s):  
Sudden Death ◽  
Functional Characterization ◽  
Missense Variant ◽  
Hek293 Cells ◽  
Patch Clamp Technique ◽  
Gene Encoding ◽  
Heterozygous Variant ◽  
Cardiac Sodium Channel ◽  
Electrophysiological Measurements

Abstract Background Alterations in the SCN5A gene encoding the cardiac sodium channel Nav1.5 have been linked to a number of arrhythmia syndromes and diseases including long-QT syndrome (LQTS), Brugada syndrome (BrS) and dilative cardiomyopathy (DCM), which may predispose to fatal arrhythmias and sudden death. We identified the heterozygous variant c.316A > G, p.(Ser106Gly) in a 35-year-old patient with survived cardiac arrest. In the present study, we aimed to investigate the functional impact of the variant to clarify the medical relevance. Methods Mutant as well as wild type GFP tagged Nav1.5 channels were expressed in HEK293 cells. We performed functional characterization experiments using patch-clamp technique. Results Electrophysiological measurements indicated, that the detected missense variant alters Nav1.5 channel functionality leading to a gain-of-function effect. Cells expressing S106G channels show an increase in Nav1.5 current over the entire voltage window. Conclusion The results support the assumption that the detected sequence aberration alters Nav1.5 channel function and may predispose to cardiac arrhythmias and sudden cardiac death.

scholarly journals On-chip multiplexed single-cell patterning and controllable intracellular delivery

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Zaizai Dong ◽  
Yanli Jiao ◽  
Bingteng Xie ◽  
Yongcun Hao ◽  
Pan Wang ◽  
...  
Keyword(s):  
Single Cell ◽  
Low Voltage ◽  
Transfection Efficiency ◽  
Cell Damage ◽  
Intracellular Delivery ◽  
Cell Manipulation ◽  
Expression Vectors ◽  
Vacuum System ◽  
Low Efficiency ◽  
On Chip

Abstract Conventional electroporation approaches show limitations in the delivery of macromolecules in vitro and in vivo. These limitations include low efficiency, noticeable cell damage and nonuniform delivery of cells. Here, we present a simple 3D electroporation platform that enables massively parallel single-cell manipulation and the intracellular delivery of macromolecules and small molecules. A pyramid pit micropore array chip was fabricated based on a silicon wet-etching method. A controllable vacuum system was adopted to trap a single cell on each micropore. Using this chip, safe single-cell electroporation was performed at low voltage. Cargoes of various sizes ranging from oligonucleotides (molecular beacons, 22 bp) to plasmid DNA (CRISPR-Cas9 expression vectors, >9 kb) were delivered into targeted cells with a significantly higher transfection efficiency than that of multiple benchmark methods (e.g., commercial electroporation devices and Lipofectamine). The delivered dose of the chemotherapeutic drug could be controlled by adjusting the applied voltage. By using CRISPR-Cas9 transfection with this system, the p62 gene and CXCR7 gene were knocked out in tumor cells, which effectively inhibited their cellular activity. Overall, this vacuum-assisted micropore array platform provides a simple, efficient, high-throughput intracellular delivery method that may facilitate on-chip cell manipulation, intracellular investigation and cancer therapy.

Single‐Use Process Platforms for Responsive and Cost‐Effective Manufacturing

2019 ◽  
pp. 201-210
Author(s):  
Priyanka Gupta ◽  
Miriam Monge ◽  
Amelie Boulais ◽  
Nitin Chopra ◽  
Nick Hutchinson
Keyword(s):  
Cost Effective ◽  
Single Use
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