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

This thesis is concerned with the development and characterisation of polymeric nanoporous adsorbents to be used for blood purification. Current treatment methods for suffers of chronic renal failure are limited to haemodialysis, peritoneal dialysis and organ transplant. Organ transplant is the most efficient option however lack of donor organs mean that the majority of suffers rely on dialysis. Unfortunately both dialysis treatments are lacking when it comes to the removal of middle molecular weight molecules (MMs) (500 - 60000 Da) and the accumulation of these molecules has been attributed to a number of additional ailments suffered by those on long term dialysis. Sorbent augmented dialysis has been identified as a potential avenue to remove these MMs, an additional column would be introduced to the haemodialysis loop this would contain adsorbent particles to remove these unwanted molecules. Styrene-divinylbenzne copolymers have been identified as suitable for this task as they will non-specifically adsorb a wide range of molecules. One major concern with the introduction of a polymeric adsorbent is the potential removal of human serum albumin HSA from the patient’s blood, this essential blood protein is present in very high concentrations typically 40g/l and this will potentially swamp the surface of any adsorbent. Fortunately HSA is a large blood protein (69kDa) and as such the method to combat this limitation as explored in this thesis is to tailor the pore structure of the polymeric adsorbent to size exclude albumin while retaining sufficient adsorption capacity to remove the MMs. To achieve these goals a number of polymeric adsorbents were generated using different porogens and degrees of crosslinking to control the porous structure. These adsorbents were analysed using a number of characterisation methods to assess their dry and swollen state porosities and molecular weight cut offs. Once a suitable material had been developed protein adsorption studies were carried out to confirm the size exclusion of HSA and the uptake of MMs.