AMF - Rotary valve carryover and dead volumes
Mar 2024

Microfluidics rotary valve carryover and dead volumes

In the field of fluidic components, internal volumes play a particularly important role. Amongst them, dead volumes (liquid trapped) and carryover volume (or contamination volume) play an even more critical role in microfluidic fluid handling. Microfluidic experiments are so sensitive and involve such small quantities of liquids that every drop counts and can have an impact in downstream operations/measurements.

At AMF, we develop solutions that enhance the efficiency and accuracy of microfluidic experiments across various fields including biomedical research, pharmaceutical development, and environmental analysis.

Understanding Key Concepts: Dead Volume and Carryover

Firstly, what is the internal volume in microfluidics? It encompasses the entire fluid pathway within a microfluidic setup, from entrance to exit, including the liquid in tubings, the microfluidic chip, and the microfluidic valve itself.

What is Dead Volume?

Dead volume is a critical concern in microfluidics, referring to the liquid trapped within a system, known as unswept volume, resulting in significant reagent waste and diminished experiment accuracy.

To clarify:

  • Swept Volume refers to the liquid (Fluid) that actively moves through our channels.
  • Unswept Volume or Dead Volume is the liquid (Fluid) that remains stagnant, no longer moving within the system.

In applications like droplet microfluidics, dead volumes can lead to issues such as droplet trapping or splitting. This is particularly problematic when working with suspensions common in microfluidics, like cells, particles, or colloids.

This challenge is really important to avoid cross-contamination, see even in the worst case, the creation of biofilm.

Put simply, dead volume represents the portion of the system that cannot be flushed out. For biochemists, it’s considered a major issue because it’s where cells and molecules can become stuck, leading to contamination and skewed results in every measurement.

What is the carryover volume in microfluidics?

Carryover, or contamination volume, is the volume of liquid inadvertently carried over with the next fluid. Unlike dead volume, carryover does not remain trapped but can still compromise the purity and results of subsequent fluid samples, leading to potential contamination of the following volumes.

Valve Technology and Principles: Minimizing Dead Volume and Carryover

To better understand carryover volume and dead volume, here’s a diagram showing the parts of a valve – including the stator and rotor – as well as the connectors, which include radial and axial ports. Fluid 1 enters through the radial port and exits via the axial port. Then, the rotor rotates, allowing Fluid 2 to enter through the radial port and exit through the axial port.

Distribution valve working principle


Switch valve principle of working

It is essential to understand that valve carryover volume equals the volume in the plug plus the volume from plug to port. This equation is fundamental in designing valves that minimize carryover and dead volume.

Advanced Solutions with AMF Products

All our products embody advanced technology designed to minimize dead volumes and prevent carryover. We meticulously design our valves with a precise roundly shaped 90-degree angle, ensuring that there are no unswept volumes, which guarantees the elimination of dead volume.

AMF-Plug coupe_piece
This unique valve designs ensure precise fluid control, reducing waste and enhancing the reliability of microfluidic experiments. They excel in applications requiring high-precision fluid handling, demonstrating our zero dead volume commitment.

Here is an example of how AMF can push the limit of carryover volume and bring it to a minimum with its unique design.


Significance in Microfluidic Experiments

Eliminating dead volumes and reducing carryover are vital for achieving accurate dosing and consistent results, crucial for advancing research in life sciences, diagnostics, and drug discovery. Integrating AMF’s microfluidic technology helps reduce cross-contamination and ensures efficient resource use in a variety of scientific studies.

Unveiling the Benefits of AMF Microfluidic Solutions

Choosing AMF’s microfluidic solutions offers multiple benefits:

  • Enhanced Accuracy and Precision: By eliminating dead volumes and minimizing carryover, our products ensure that experiments are as accurate as possible.
  • Cost Efficiency: Our technology reduces the need for expensive reagents and minimizes waste, offering significant cost savings over time.
  • Versatility: Our range of microfluidic valves is suitable for a variety of applications, from drug development to environmental monitoring.
  • Customization: We provide customized solutions to meet specific research needs, ensuring that our clients can tackle unique challenges effectively.

At Advanced Microfluidics SA, we are committed to pushing the boundaries of microfluidic technologies. Our product range exemplifies our dedication to enhancing precision, efficiency, and reliability in your experiment. Revolutionize your research and development efforts by embracing the future of microfluidics with AMF.

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