Functionalized bicomponent polymer membranes as supports for covalent immobilization of enzymes

The present work was aimed at developing new reactive polymer materials suitable to be used as supports for enzyme covalent immobilization. Thus, new bicomponent polymer membranes were developed using poly(acrylonitrile-co-vinyl acetate) (PAN-co-PVAc) in mixture with polyvinyl alcohol (PVA). First of all, PAN-co-PVAc/PVA blends were dissolved in DMSO, until a homogenous polymer solution was obtained. To prepare membranes, these solutions were cast on a glass plate followed by the immersion of this plate in a coagulation bath containing a 50%-50% (volume %) water-isopropyl alcohol mixture. In this way membranes containing OH functional groups were obtained. Before tyrosinase immobilization, membranes were functionalized with glutardialdehyde; hence CHO binding sites were inserted and membrane became reactive for the enzyme. In order to prove that both, functionalization and immobilization reactions, were successful, the modifications produced by these reactions were investigated by various techniques i.e. Fourier Transform Infrared Spectrometry, Thermal Gravimetric Analysis, Differential Scanning Calorimetry and Atomic Force Microscopy. The occurrence of important changes in membrane features confirmed the success of both reactions. Furthermore, the activity of bonded enzyme was determined by pyrocatechol method and compared to the activity of the free enzyme.