Wet Foam Elution

Rapid recovery of captured biological particles using Wet Foam Elution™

The Wet Foam Elution process requires very specific high-quality foam in order to be effective.  The elution fluid is composed of water, a low concentration surfactant (less than 0.1%), a pH buffer, and infused with carbon dioxide. During the extraction process, the dissolved carbon dioxide expands and comes out of solution to form microbubbles. These microbubbles increase the volume of the fluid sevenfold or more as it recovers the biological organisms from the filter consumable. Upon elution, the foam immediately off-gasses and collapses into a liquid and the concentrated sample is ready for analysis.

An additional benefit of Wet Foam Elution is the buffer exchange. In many situations the starting sample matrix is not the most desirable for the chosen analysis method. Wet Foam Elution provides a clean buffer for the biological particles to be suspended, which can reduce inhibition and maximizes detection.

How it works

Particles are captured onto a membrane by dead-end filtration and are then recovered into a significantly reduced sample volume.  Wet Foam Elution, was developed by InnovaPrep and is a critical component in InnovaPrep products.  The Wet Foam Elution process is similar to how liquid would be used to tangentially rinse particles off of a membrane filter; however, it is much more efficient than liquid rinsing for the following reasons:

Volume Expansion

When rinsing a filter with liquid, most of the liquid volume is used to fill the dead space inside the filter housing; only a small portion of the fluid is actually in contact with the filter surface. This can be minimized to an extent by reducing the cross-sectional area of the fluid path across the filter, but a large portion of the liquid is still underutilized. Foam however is 80-90% gas, which fills the empty space without contributing to the final sample volume.

Increased Viscosity

Liquid has a tendency toward “channeling” when flowing across a surface, that is, there is an area of high flow in the center of the fluid path while the portion of flow in contact with the filter surface is much slower. The higher viscosity of foam prevents channeling and creates a more uniform flow across the filter surface.

Bubble Dynamics

The microbubbles in the foam behave as deformable solids. As they travel across the surface of the filter they move as a ridged body with a narrow lubricating layer; effectively squeegeeing the particles off of the surface.

Exfoliating Action

As the microbubbles in the foam impact against each other and burst, the turbulence and energy produced helps to lift particles that are adhering to the membrane.

Available Elution Fluids include:

0.075% Tween 20/ PBS – Recommended for classical culture analysis   SDS

item # HC08000-6 (Concentrating Pipette)

item # AC00201-P (Bobcat)

0.075%Tween 20/ Tris – Recommended for rapid analysis methods      SDS

item # HC08001 (Concentrating Pipette)

item # AC00201-T (Bobcat)