Application of single-pore membranes in hemorheological research

Abstract

A method has been developed, which measures the passage of single blood cells through a single pore filter at a low constant pressure gradient. The cell passage through the pore is descriminated into entry, transit and exit phase. Passage times are not below 10 ms and thus long enough to distinguish from any “background” noise. A batch of filters with different diameters (between 4.0 and 6.0 μm) was reused after ultra-sonication for 10 s in 1 % w/v sodium dodecyl sulphate. Cell transit was measured at different pressure gradients (Δp: 100 to 600 Pa). We could measure a strong dependency of RBC passage through the single pore filter on pore diameter and pressure gradient. Also different amounts (“subpopulations”) of rigid RBC's or WBC's in the RBC-suspension (hct: 1 %) influences the test results. A temperature controlled measuring chamber enables us to demonstrate the significant effect of temperature on blood cell rheology. This improved device, called Cell Passage Analyser (CPA), - using single pore filters and well defined low pressure gradients represents a measuring device for reproducible and reliable rheological investigations concerning red (RBC) and white blood cell (WBC) deformability.