The Experts below are selected from a list of 17826 Experts worldwide ranked by ideXlab platform
Aldo Jesorka - One of the best experts on this subject based on the ideXlab platform.
-
a multifunctional Pipette
Lab on a Chip, 2012Co-Authors: Alar Ainla, Gavin D M Jeffries, Ralf Brune, Owe Orwar, Aldo JesorkaAbstract:Microfluidics has emerged as a powerful laboratory toolbox for biologists, allowing manipulation and analysis of processes at a cellular and sub-cellular level, through utilization of microfabricated features at size-scales relevant to that of a single cell. In the majority of microfluidic devices, sample processing and analysis occur within closed microchannels, imposing restrictions on sample preparation and use. We present an optimized non-contact open-volume microfluidic tool to overcome these and other restrictions, through the use of a hydrodynamically confined microflow Pipette, serving as a multifunctional solution handling and dispensing tool. The geometries of the tool have been optimised for use in optical microscopy, with integrated solution reservoirs to reduce reagent use, contamination risks and cleaning requirements. Device performance was characterised using both epifluorescence and total internal reflection fluorescence (TIRF) microscopy, resulting in ∼200 ms and ∼130 ms exchange times at ∼100 nm and ∼30 μm distances to the surface respectively.
-
a microfluidic Pipette for single cell pharmacology
Analytical Chemistry, 2010Co-Authors: Alar Ainla, Owe Orwar, Erik T Jansson, Natalia Stepanyants, Aldo JesorkaAbstract:We report on a free-standing microfluidic Pipette made in poly(dimethylsiloxane) having a circulating liquid tip that generates a self-con-fining volume in front of the outlet channels. The method is flexible and scalable as the geometry and the size of the recirculation zone is defined by pressure, channel number, and geometry. The Pipette is capable of carrying out a variety of complex fluid processing operations, such as mixing, multiplexing, or gradient generation at selected cells in cell and tissue cultures. Using an uptake assay, we show that it is possible to generate dose response curves in situ from adherent Chinese hamster ovary cells expressing proton-activated human transient receptor potential vanilloid (hTRPV1) receptors. Using confined superfusion and cell stimulation, we could activate hTRPV1 receptors in single cells, measure the response by a patch-clamp Pipette, and induce membrane bleb formation by exposing selected groups of cells to formaldehyde/dithiothreitol-containing solutions, respectively. In short, the microfluidic Pipette allows for complex, contamination-free multiple-compound delivery for pharmacological screening of intact adherent cells.
Edward S Boyden - One of the best experts on this subject based on the ideXlab platform.
-
patcherbot a single cell electrophysiology robot for adherent cells and brain slices
Journal of Neural Engineering, 2019Co-Authors: Ilya Kolb, Corey R Landry, Mighten C Yip, Colby F Lewallen, William A Stoy, John Lee, Amanda Felouzis, Bo Yang, Edward S BoydenAbstract:OBJECTIVE Intracellular patch-clamp electrophysiology, one of the most ubiquitous, high-fidelity techniques in biophysics, remains laborious and low-throughput. While previous efforts have succeeded at automating some steps of the technique, here we demonstrate a robotic 'PatcherBot' system that can perform many patch-clamp recordings sequentially, fully unattended. APPROACH Comprehensive automation is accomplished by outfitting the robot with machine vision, and cleaning Pipettes instead of manually exchanging them. MAIN RESULTS the PatcherBot can obtain data at a rate of 16 cells per hour and work with no human intervention for up to 3 h. We demonstrate the broad applicability and scalability of this system by performing hundreds of recordings in tissue culture cells and mouse brain slices with no human supervision. Using the PatcherBot, we also discovered that Pipette cleaning can be improved by a factor of three. SIGNIFICANCE The system is potentially transformative for applications that depend on many high-quality measurements of single cells, such as drug screening, protein functional characterization, and multimodal cell type investigations.
Jef Vandenberghe - One of the best experts on this subject based on the ideXlab platform.
-
comparison of laser grain size analysis with Pipette and sieve analysis a solution for the underestimation of the clay fraction
Sedimentology, 1997Co-Authors: Martin Konert, Jef VandenbergheAbstract:Classically, the grain size of soil and sediment samples is determined by the sieve method for the coarse fractions and by the Pipette method, based on the ‘Stokes’ sedimentation rates, for the fine fractions. Results from the two methods are compared with results from laser diffraction size analysis, which is based on the forward scattering of monochromatic coherent light. From a point of view of laboratory efficiency, the laser sizing technique is far superior. Accuracy and reproducibility are shown by measurements on certified materials. It appears that laser grain size measurements of certified materials correspond very well with the certificated measurements. Tests were also done on a set of randomly selected sediments of fluvial, aeolian and lacustrine origin. Except for the (<2 μm) clay fraction, there is a coarsening of the mean diameter of one to two size classes (0.25 ɛ), caused by the non-sphericity of the particles. The platy form of the clay particles induces considerable differences (eight size classes) between Pipette and laser measurements: the <2 μm grain size, defined by the Pipette method corresponds with a grain size of 8 μm defined by the Laser Particle Sizer for the studied sediments. Using a higher grain size level for the clay fraction, when laser analysis is applied, enables workers in the geological and environmental field to compare classical Pipette analysis with a laser sizing technique.
Alar Ainla - One of the best experts on this subject based on the ideXlab platform.
-
a multifunctional Pipette
Lab on a Chip, 2012Co-Authors: Alar Ainla, Gavin D M Jeffries, Ralf Brune, Owe Orwar, Aldo JesorkaAbstract:Microfluidics has emerged as a powerful laboratory toolbox for biologists, allowing manipulation and analysis of processes at a cellular and sub-cellular level, through utilization of microfabricated features at size-scales relevant to that of a single cell. In the majority of microfluidic devices, sample processing and analysis occur within closed microchannels, imposing restrictions on sample preparation and use. We present an optimized non-contact open-volume microfluidic tool to overcome these and other restrictions, through the use of a hydrodynamically confined microflow Pipette, serving as a multifunctional solution handling and dispensing tool. The geometries of the tool have been optimised for use in optical microscopy, with integrated solution reservoirs to reduce reagent use, contamination risks and cleaning requirements. Device performance was characterised using both epifluorescence and total internal reflection fluorescence (TIRF) microscopy, resulting in ∼200 ms and ∼130 ms exchange times at ∼100 nm and ∼30 μm distances to the surface respectively.
-
a microfluidic Pipette for single cell pharmacology
Analytical Chemistry, 2010Co-Authors: Alar Ainla, Owe Orwar, Erik T Jansson, Natalia Stepanyants, Aldo JesorkaAbstract:We report on a free-standing microfluidic Pipette made in poly(dimethylsiloxane) having a circulating liquid tip that generates a self-con-fining volume in front of the outlet channels. The method is flexible and scalable as the geometry and the size of the recirculation zone is defined by pressure, channel number, and geometry. The Pipette is capable of carrying out a variety of complex fluid processing operations, such as mixing, multiplexing, or gradient generation at selected cells in cell and tissue cultures. Using an uptake assay, we show that it is possible to generate dose response curves in situ from adherent Chinese hamster ovary cells expressing proton-activated human transient receptor potential vanilloid (hTRPV1) receptors. Using confined superfusion and cell stimulation, we could activate hTRPV1 receptors in single cells, measure the response by a patch-clamp Pipette, and induce membrane bleb formation by exposing selected groups of cells to formaldehyde/dithiothreitol-containing solutions, respectively. In short, the microfluidic Pipette allows for complex, contamination-free multiple-compound delivery for pharmacological screening of intact adherent cells.
Allen P Liu - One of the best experts on this subject based on the ideXlab platform.
-
a microfluidic Pipette array for mechanophenotyping of cancer cells and mechanical gating of mechanosensitive channels
Lab on a Chip, 2015Co-Authors: Lap Man Lee, Allen P LiuAbstract:MicroPipette aspiration measures the mechanical properties of single cells. A traditional microPipette aspiration system requires a bulky infrastructure and has a low throughput and limited potential for automation. We have developed a simple microfluidic device which is able to trap and apply pressure to single cells in designated aspiration arrays. By changing the volume flow rate using a syringe pump, we can accurately exert a pressure difference across the trapped cells for Pipette aspiration. By examining cell deformation and protrusion length into the Pipette under an optical microscope, several important cell mechanical properties, such as the cortical tension and the Young's modulus, can be measured quantitatively using automated image analysis. Using the microfluidic Pipette array, the stiffness of breast cancer cells and healthy breast epithelial cells was measured and compared. Finally, we applied our device to examine the gating threshold of the mechanosensitive channel MscL expressed in mammalian cells. Together, the development of a microfluidic Pipette array could enable rapid mechanophenotyping of individual cells and for mechanotransduction studies.
