Nanofibrous Affinity Membranes Containing Non-Antibody Binding Proteins

The specific removal of molecules from various media is an area receiving increasing attention. Affnity membranes, i.e. membranes containing ligands, which can specifically capture target molecules, can meet this demand. One important area, in which the use of affinity membranes will be beneficial, is blood filtration, specifically haemodialysis treatments. The specific removal of toxins can reduce treatment time and/or frequency and therefore increase patients' quality of life as well as reduce costs for the health care sector. The presented research investigates the feasibility of combining a new class of nonantibody binding proteins (AdhironTM binders), which can be specifically designed to capture target molecules, with electrospun nanofibrous polysulphone (PSu) membranes to create an affinity membrane for the specific removal of target molecules. Adhiron binders against a model target protein (modified green fluorescent protein (mGFP)) were successfully produced and characterised. Suitable parameters for the electrospinning of PSu into smooth bead-free fibres were identified. Two different approaches for the functionalisation of PSu fibres were evaluated: incorporation of the Adhiron binders within the fibre and attachment of the binders to the functionalised PSu fibre surfaces. With the latter approach functionalisation was achieved by means of attaching Adhiron binders to surface functionalised fibres, on which the Adhiron binders were immobilised via a biotin-streptavidin bridge. The functionalised membrane specifically removed target molecules out of simple and complex solutions.