Basic principles for evaluation of less deformable erythrocyte subpopulations with the Microfiltrometer

Abstract

The Microfiltrometer consists of a filtration system for diluted erythrocyte suspensions, through a filter containing 30 cylindrical micropores, 5 microm in diameter, under the influence of a driving pressure. A feeding sinusoidal alternating current of 40 kHz, 300 microA is delivered to the filter. The change in impedance is collected for each temporary flow of erythrocytes through a given micropore. Two main parameters are measured for individually explored erythrocytes: the entry time tau in the micropore and the maximal variation of impedance deltaZ occurring for the transitory flow. The slope deltaZ/tau defines the velocity of pore blockage. A "Microfiltrometer Deformability Index" (MDI) is established by using this slope. When MDI > or = 1, the erythrocyte is considered to be deformable and, conversely, when MDI < 1, the erythrocyte is considered to be undeformable. Using this procedure, less than 2% undeformable erythrocytes in healthy blood samples are identified, with a specificity of 99% and a sensitivity of 97.5%.

Production of multi-, oligo- and single-pore membranes using a continuous ion beam

“…The technique for producing single ion tracks in thin plastic films has become important in connection with extensive research in the field of novel nanofluidic phenomena and the development of miniaturized devices, such as molecular valves, ion pumps, and logic elements [1]. Apart from single-pore membranes, membranes with few pores (the number of which is known) are also useful in microfluidics [5,6]. The production of single-and oligo-pore membranes generally requires sophisticated equipment, including a heavy-ion accelerator, a specialized beam line with a detector to detect single hits and a beam switch capable of interrupting the beam after every hit [1,7,8].…”