Ultrafiltration membrane surfaces with grafted polymer ‘tentacles’: preparation, characterization and application for covalent protein binding

摘要: Abstract Ultrafiltration (UF) membranes from polysulfone (PSf) were functionalized by heterogeneous photo-initiated graft copolymerization of acrylic acid (AA). With radiation susceptible PSf, only proper selection the UV energy ( λ >350 nm; for selective excitation photoinitiator) yielded with preserved UF barrier layer. Possibilities adjusting structure and morphology polymer (g-PAA) layer variation functionalization parameters such as AA concentration irradiation time investigated. Very long grafted chains M W >10 5  g mol -1 ) at varied grafting density (GD=0.01…1.2 nmol cm -2 , relative to outer surface area) obtained. Partial penetration g-PAA was verified. Covalent immobilization bovine serum albumin (BSA), γ -globulin -Gl) alkaline phosphatase (APh) achieved coupling a water soluble carbodiimide. Bound BSA -Gl amounts up Γ=10 μg cm accessible thus not using entire pore volume. Locally addressed covalent protein after photo-patterning PSf could be visualized fluorescent FITC-BSA conjugate. A strong salt effect onto immobilized APh activity (increase NaCl concentration) observed, indicating internal transport/accessibility limitations in Correlations between PAA w GD) accessibility (from or binding activity) established. The ‘tentacle’ having and, e.g., surface-bound receptors will find application cell cultures under diffusion perfusion conditions.