A small piezoelectric device for cell penetration is described. It retracts the micropipette slowly by electrostriction, and pushes it very fast (less than 5 microsecond) forward by short-circuiting the transducer. The design, operation circuit, and performance under test conditions are described. Penetration examples from small nerve fibers (less than 5 micrometer) show that membrane puncture ...

Glass capillaries with diameters of 1.5 mm were used. The tips of the capillaries were sharpened by a flaming-brown micropipette puller (Model P-1000, Sutter Instrument, USA) to obtain needle-shape capillaries. Anhydrous alcohol (99.5%) and anhydrous toluene (99.9%) were purchased from Shimakyus Pure Chemical (Osaka, Japan) and J. T. Baker (Phillipsburg, NJ, USA). MTS (Methyltrichlorosilane, CH...

MATERIALS Reagents Dithiothreitol (DTT), 1 M DNA IQ System (Promega; includes Resin, Lysis Buffer, 2X Wash Buffer, and Elution Buffer) Ethanol, 95-100% Isopropanol Sample (liquid blood, cotton swab, th CEP swab, 15-50 mm2 S&S paper, 3-30 mm2 FTA paper) Equipment Aerosol-resistant micropipette tips DNA IQ Spin Baskets (Promega) Heating blocks, preset to 65°C and 95oC MagneSphere Technology Magne...

For determination of possible neurotransmitters synthesized by photoreceptor cells, turtle retinas were dissociated into single cells with proteolytic enzymes. These cells were partially separated by velocity sedimentation to yield a fraction rich in photoreceptors. Individual photoreceptor cells were then sucked into a micropipette and incubated with labeled precursors of known or suspected ne...

Abstract Patch clamp recording of neurons is a labor-intensive and time-consuming procedure. Here, we demonstrate tool that fully automatically performs electrophysiological recordings in label-free tissue slices. The automation covers the detection cells images, calibration micropipette movement, approach to cell with pipette, formation whole-cell configuration, recording. based on deep learni...

Coarse-grained molecular models of the erythrocyte membrane's spectrin cytoskeleton are presented in Monte Carlo simulations of whole cells in micropipette aspiration. The nonlinear chain elasticity and sterics revealed in more microscopic cytoskeleton models (developed in a companion paper; Boey et al., 1998. Biophys. J. 75:1573-1583) are faithfully represented here by two- and three-body effe...

The effects of mechanical perturbations (shear stress, pressure) on microvascular permeability primarily have been examined in micropipette-cannulated vessels or in endothelial monolayers in vitro. The objective of this study is to determine whether acute changes in blood flow shear stress might influence measurements of hydraulic conductivity (L(p)) in autoperfused microvessels in vivo. Rat me...

The mechanical properties of cultured bovine aortic endothelial cells exposed to a fluid-imposed shear stress were studied using the micropipette technique. The cells, which were attached to a Thermanox plastic substrate, were exposed to a specific steady shear stress of either 10, 30, or 85 dynes/cm2 and for a duration ranging from 0.5 to 24 hours. Morphological changes in shape and orientatio...

Mechanical dissociation of neurons from the central nervous system has the advantage that presynaptic boutons remain attached to the isolated neuron of interest. This allows for examination of synaptic transmission under conditions where the extracellular and postsynaptic intracellular environments can be well controlled. A vibration-based technique without the use of proteases, known as vibrod...

Microscopic lymphatics produce nitric oxide (NO) during contraction as flow shear activates the endothelial cells. The valve leaflets and bulbous valve housing contain a large amount of endothelial nitric oxide synthase (eNOS) due both to many endothelial cells and increased expression of eNOS. Direct NO measurements indicate the valve area has a 30-50% higher NO concentration ([NO]) than tubul...