Binding Properties of Filters

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If you are filtering a sample containing analytes or other valuable components of interest, you need to be confident that these analytes are not lost by binding to the filtration device, and that the molecular composition of the filtrate is what you expect.

Because the internal surface area of polymeric microporous membranes is 100–600 times as great as the frontal surface area, there is a vast internal surface area available for nonspecific binding. Of all membranes evaluated, the hydrophilic PVDF microporous membrane was found to be extremely inert and has both the lowest protein binding properties and the highest product recovery.

Lowest Protein Binding

Data from research conducted by Merck on the protein binding properties of selected filters are summarized in this chart:
Protein Adsorption to Polymer Surfaces
µg Protein Bound/cm2 Frontal Areang Protein Bound/cm2 BET* Area>
Membrane BSA IgG BSA IgG
Hydrophilic PVDF 3.4 3.8 6.4 7.0
Nylon 196.4 190.6 353.0 342.0
Hydrophilic Polysulfone 3.4 13.4 11.0 43.0
Mixed esters of cellulose 273.6 238.2 2540.0 2210.0
*BET membrane surface area includes the total internal surface area of a porous membrane structure

Highest Product Recovery

Data on the product recovery properties of selected filters are summarized in this chart:
Product Recovery of Selected Filters
Product Recovery (%)
BSA Bound(2) (µg)

Hydrophilic PVDF



Nylon 83.6 1018.4
Hydrophilic Polysulfone 99.6 21.6
Mean of 2-3 experiments
(2) µg BSA bound/cm2 membrane frontal area.
The hydrophilic PVDF membrane consistently demonstrated the highest product recovery when tested in a dynamic sterile filtration mode.

More information on the performance of these filters