Characterization and functionalization of cellulose microbeads for extracorporeal blood purification

In the frame of this work, cellulose microbeads with an average particle size of 2.3 μm were characterized with respect to porosity using a batch solute exclusion method and two groups of model substances, namely proteins and polystyrene sulfonates. The pores of the microbeads were almost completely accessible to proteins with Stokes radii below 2.5 nm. More than 60% of the pores were accessible to albumin, which is relevant for the application in blood purification, since many target substances are albumin bound. Activation of the microbeads with increasing amounts of sodium metaperiodate yielded matrices with dialdehyde contents between 100 and 1,000 μmol/g. The activated beads were well suited for the covalent attachment of functional ligands, such as antibodies. Immobilization of antibodies against the pro-inflammatory cytokine TNF-α resulted in efficient TNF-α adsorbents which possess application potential in extracorporeal blood purification, e.g. for the modulation of cytokine levels as supportive therapy for sepsis and other inflammatory disorders.