Photo-crosslinked PVA/PEI electrospun nanofiber membranes: Preparation and preliminary evaluation in virus clearance tests

We report on the preparation of electropositive nanofiber membranes by electrospinning with in situ photo-crosslinking and their preliminary evaluation in virus adsorption and removal tests. Poly(vinyl alcohol) (PVA) and polyethyleneimine (PEI) were modified with glycidyl methacrylate, to form an acrylated crosslinked polymer (a-PVA/a-PEI) upon UV exposure during the electrospinning process. The a-PVA/a-PEI nanofibers were electrospun on a non-woven polyester support to form an electropositive (ζ = 7 mV at pH 7.4) and hydrophilic (θ_w∼53^°) membrane with the mean pore size of 0.48 μm. The microfilter had the specific permeate flux of ∼6.9 · 10⁴ L/(m²·h·bar), comparable with that of commercially available membranes of similar nominal pore sizes. Adsorption of the negatively charged and hydrophilic bacteriophage MS2 (d∼27 nm) onto the membrane followed Freundlich isotherm and could be classified as favorable with the average adsorption intensity n^-1∼0.91. The 99% retention of MS2 in flow-through virus clearance tests was attributed to adsorption and was likely controlled by the limited detention time within the membrane.