Capillary Valving
Capillary Valving - Related Videos
08:50
Capillary Electrophoresis (CE)
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2023
Source: Laboratory of Dr. B. Jill Venton - University of Virginia Capillary electrophoresis (CE) is a separation technique that separates molecules in an electric field according to size and charge. CE is performed in a small glass tube called a capillary that is filled with an electrolyte solution. Analytes are separated due to differences in electrophoretic mobility, which varies with charge, solvent viscosity, and size. Traditional electrophoresis in gels is limited in the amount of voltage...
14:53
Capillary Electrophoresis Separation of Monoclonal Antibody Isoforms Using a Neutral Capillary
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Cited by 2 •
2017
Here, we present a comprehensive capillary zone electrophoresis protocol for the assessment of intrinsic physicochemical heterogeneity of monoclonal antibodies as a quality attribute.
03:45
Purifying Capillaries From a Porcine Brain
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2025
This video demonstrates the isolation of capillaries from fresh porcine brains. The process involves removing the meninges, isolating the grey matter from the brain tissue, homogenizing and filtering the grey matter to isolate the capillaries, and finally using enzymatic digestion to purify the capillaries further.
08:55
Isolation and Characterization of Primary Rat Valve Interstitial Cells: A New Model to Study Aortic Valve Calcification
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Cited by 16 •
2017
This protocol describes the isolation, culture, and calcification of rat-derived valve interstitial cells, a highly physiological in vitro model of calcific aortic valve disease (CAVD). Exploitation of this rat model facilitates CAVD research in exploring the cell and molecular mechanisms that underlie this complex pathological process.
01:20
Capillary Beds
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2024
Capillary beds are networks of tiny blood vessels that play a crucial role in the circulatory system. These beds are where the exchange of gases, nutrients, and waste products occurs between the blood and surrounding tissues. Each capillary bed consists of numerous capillaries, which are the smallest blood vessels in the body, typically only one cell-thick. This thinness allows for the efficient diffusion of substances. Capillaries connect arterioles, small branches of arteries, to venules,...
FAQs
At a valve, liquid motion depends on whether capillary forces can overcome the opposing pressure conditions. Surface tension and the liquid’s contact angle establish how strongly the interface tends to advance along the channel, while the valve geometry determines where that advance is arrested. Adjusting these variables changes the pressure balance, allowing a designed pause or release.
Channel geometry is not merely a pathway feature; it helps set the capillary pressure balance. Narrow-channel dimensions and changes in channel shape can create a location where liquid pauses, then permit passage when conditions change. This makes geometry a design variable for routing liquid between chambers and coordinating when downstream reagents become available.
A capillary valve can be triggered by changing wettability or applying pressure. A wettability change alters how the liquid interacts with the channel surface, whereas applied pressure directly shifts the force balance that holds the liquid at the valve. These triggers provide control when needed while retaining the underlying capillary mechanism and avoiding continuously pumped flow.
Reliable operation requires consistent surface and geometric conditions because contact angle, wettability, surface tension, and pressure balance jointly determine the outcome. If one of these factors changes, the same valve may pause, release, or route liquid differently. Controlling these variables is therefore important for reproducible reagent delivery and reaction timing in small-volume chemical assays.
Design begins by selecting channel geometry and surface conditions that establish the desired pressure balance. The valve is then positioned within a flow path so liquid can pause before a chamber or pass onward after a trigger. During operation, liquid is introduced, the valve condition is maintained or changed, and movement is observed as chambers fill, reagents are delivered, or steps proceed.
Compared with pump-driven microfluidics, capillary valving relies on the liquid, channel design, and pressure balance to control movement rather than requiring pumps or complex controllers. This passive approach can simplify compact devices and reduce operational demands. It is especially relevant when portability, small sample and reagent volumes, and coordinated multistep processing are priorities.
In chemistry, capillary valving supports paper-based tests and lab-on-a-chip platforms by coordinating reagent delivery, mixing, and reaction timing. Routing liquid between chambers enables multistep assays without complex external control. These systems can improve portability and use smaller sample and reagent volumes, making compact analytical devices more practical for chemically coordinated workflows.