Haemocompatibility and ion exchange capability of nanocellulose polypyrrole membranes intended for blood purification

Composites of nanocellulose and the conductive polymer polypyrrole (PPy) are presented as candidates for a new generation of haemodialysis membranes. The composites may combine active ion exchange with passive ultrafiltration, and the large surface area (about 80 m2 g−1) could potentially provide compact dialysers. Herein, the haemocompatibility of the novel membranes and the feasibility of effectively removing small uraemic toxins by potential-controlled ion exchange were studied. The thrombogenic properties of the composites were improved by applying a stable heparin coating. In terms of platelet adhesion and thrombin generation, the composites were comparable with haemocompatible polymer polysulphone, and regarding complement activation, the composites were more biocompatible than commercially available membranes. It was possible to extract phosphate and oxalate ions from solutions with physiological pH and the same tonicity as that of the blood. The exchange capacity of the materials was found to be 600 ± 26 and 706 ± 31 μmol g−1 in a 0.1 M solution (pH 7.4) and in an isotonic solution of phosphate, respectively. The corresponding values with oxalate were 523 ± 5 in a 0.1 M solution (pH 7.4) and 610 ± 1 μmol g−1 in an isotonic solution. The heparinized PPy–cellulose composite is consequently a promising haemodialysis material, with respect to both potential-controlled extraction of small uraemic toxins and haemocompatibility

Synthesis and characterization of size-selective nanoporous polymeric adsorbents for blood purification.

Crosslinked polystyrene co-divinylbenzene adsorbent microspheres with median diameters between 40 and 300 μm, with an enhanced proportion of mesopores in the range 4–10 nm, have been synthesized using a membrane emulsification technique. The aim was to develop an adsorbent for the selective removal of middle molecular weight uraemic toxins (size range 0.5–20 kDa), e.g. β2-microglobulin (11.8 kDa), whilst size-excluding larger blood proteins, e.g. serum albumin (MW 69 kDa). Using inverse size exclusion chromatography, the role of size exclusion has been demonstrated using hen egg lysozyme (a surrogate for β2-microglobulin) and human serum albumin as model proteins for batch adsorption studies. The adsorbent sample possessing a nanoporous structure with pores predominantly smaller than 10 nm successfully size-excludes serum albumin whilst displaying significant adsorption capacity for the middle molecular weight lysozyme (14.3 kDa)

An evaluation of the Baxter CA HP 210G haemodialyser

SIGLEGBUnited Kingdo

An evaluation of the Hospal Acepal 1500 haemodialyser

SIGLEGBUnited Kingdo