The permselectivity of poly(glyceryl methacrylate) membranes: hydrogel analogues of glomerular basement membrane

Abstract

The ultrafiltration behaviour of highly hydrated thin films of poly(glyceryl methacrylate) (PGMA) hydrogel has been studied and compared with the behaviour of the glomerular basement membrane (GBM). PGMA hydrogel films paralleled the behaviour of GBM as compressible ultrafilters, showing selectivity for proteins of different sizes. The pore theory and fibre-matrix hypothesis were used to model permeation behaviour. Pore radii predicted by the pore theory were 2.3–4.0 nm for PGMA and 3.5–6.0 nm for GBM. Fibre radii predicted using the fibre-matrix hypothesis generally were 0.8 ± 0.05 nm for both materials, consistent with the view that these materials are networks of randomly arranged flexing fibres. The fibre-matrix hypothesis was judged to provide a more realistic correlation between structural characteristics and permeation behaviour than the pore theory. The results indicate that GBM possesses hydogel-like properties.