A Simple Biosensor for Biogenic Diamines, Comprising Amine Oxidase-Containing Threads and Oxygen Sensor

A simple biosensor was constructed for the assessment of white fish freshness by integrating a cylindrical oxygen sensor and nylon threads with immobilized amine oxidase from pea seedlings (PSAO), having a catalytic activity of (4.58 +/- 0.40) x 10(-4) IU per 1 cm thread. Enzyme-containing threads, with a total length of 30 to 130 cm, were coiled around the cathode of an oxygen sensor in the form of winding stairs with a variable length of step, so forming a flexible bio-recognition element for biogenic amines cadaverine and/or putrescine, which could be easily renewed, replaced or modified. The variable amount of enzyme and diffusion characteristics of the system enabled to modify the sensitivity of the biosensor for nearly 8 times. Biosensor, incorporating 90 cm of PSAO-active thread and having the sensitivity of 0.81 l/mmol towards cadaverine, was used for the rapid determination of biogenic diamines in hake probes. The results, obtained with biosensor were validated using HPLC analysis.