Affinity Binding Macroporous Monolithic Cryogel as a Matrix for Extracorporeal Apheresis Medical Devices

Cytapheresis is an extracorporeal separation technique widely used in medicine for elimination of specific classesof blood cells from circulating blood. It has been shown recently to have clinical efficacy in various disease states, such as leukaemia, autoimmune disorders, rheumatoid arthritis, renal allograft rejection and sickle–cell anaemia. The current study was undertaken to produce an affinity-binding column, based upon a macroporous monolithic cryogel with a structure of interconnected pores, with pore size and low flow resistance potentially suitable for use in cytapheresis. The affinity column was produced from poly (2-hydroxyethyl methacrylate) PHEMA cryogels synthesized by free radical polymerization at -12°C. This study involved assessing haemolytic potential, and functionalisation of polymer matrix with biological ligands. Haemolytic potential of poly (2-hydroxyethyl methacrylate) cryogel was established by measuring free haemoglobin after blood filtration through the column. The anti-human albumin (antibody) was chemically coupled to the epoxy derivatised monolithic cryogels and the binding efficiency of anti-human albumin (antibody) to the cryogel was determined. Our results show that approximately 100% of Red blood cells passed through the column with no evidence of haemolysis found in blood eluted. It was found that ~82% of human serum albumin was retained on the monolithic IgG anti-human albumin cryogel matrix. The obtained results suggest that poly (2-hydroxyethyl methacrylate) monolithic cryogel is a non-haemolytic material (haemocompatible matrix) capable of functionalisation with antibody and thus can be an appropriate matrix for use inextracorporeal apheresis system.