Biofunctionalization of Dextran-Based Polymeric Film Surface through Enzyme Immobilization for Phenylalanine Determination

Many existing clinical and biochemical assays are rendered ineffective in the detection of phenylketonuria (PKU) diseases. In this study, we investigated the biofunctionalization of a dextran-based polymeric film surface through enzyme immobilization to construct an electrochemical biosensor for phenylalanine determination. This analytical device is made up of an enzyme electrode comprised of dextran, polyvinylpyrrolidone (PVP), bovine albumin serum (BSA) protein, glutaraldehyde (GA) and immobilized phenylalanine dehydrogenaze (PHD). Electroanalytical techniques including cyclic voltammetry and chronoamperometery were employed to provide experimental information about the biosensor response. Analytical experiments were repeated five times and showed a small error (~9%). The presence of GA and BSA enhanced the range of linear response and sensitivity of the constructed biosensor which confirmed by the amperommetric analysis. The current response and Michaelis-Menten response of electrode showed higher sensitivity than those of the previous works.