Ad hoc functionalization of PVDF Membranes for Tyrosinase Immobilization

Polyvinylidene fluoride (PVDF, provided by GVS-Italy) membranes were chemically activated aiming to subsequent covalent immobilization of protein molecules. The study was carried out using the tyrosinase as enzyme model [1-3]. The chemical modification was performed introducing on the membrane surface primary amino groups. Subsequently, these chemical groups were used as reactive sites for multipoint covalent attachment. In this perspective, the aminate films were activated with glutaraldehyde to promote the formation of a covalent linkage between the amino and aldehyde groups. In a next step the formation of an imine between the glutaraldehyde and the amine function of the tyrosinase allowed the covalent immobilization of the enzyme. The functionalized systems were characterized by SEM and IR analyses. The specific activity of free and immobilized enzyme was determined following the production of the L-DOPA in the time. The experimental results showed as the enzyme has maintained constant its activity, exhibiting at the same time a good stability also after the immobilization process.