Exploiting temperature dependence to improve selectivity in membrane-based plasmapheresis

Temperature effects on cross-flow membrane plasmapheresis have been investigated with the help of hydrophillic polyvinylidene fluoride (PVDF) Durapore membranes of pore size 0.65 micron and an effective filtration area 30 cm2, using a thin-channel device (Minitan-S, Millipore Inc., U.S.A.) and goat's blood as the working fluid. The filtration and sieving properties have been characterized by evaluating normal saline (0.9 g%) flux and the sieving coefficients of albumin, immunoglobulins, and fibrinogen respectively. Runs were performed at 10 +/- 1, 20 +/- 1, 30 +/- 1 and 40 +/- 1 degree C, the various filtration parameters were measured and samples of the feed and permeate were collected during steady state. It is seen that the "effective" pore size increases with temperature increase thereby increasing flux, sieving and fouling. Exploiting temperature effects can possibly help modify the sieving spectrum in membrane-based plasmapheresis.