Design of a new biosensor for the determination of iron in blood

Iron is found in the structure of many proteins and enzymes. Iron is involved in the transport of oxygen to the tissues, however, it plays a key role in the development and differentiation of cells. The amount of ıron deficiency affects 30% of the world population according to WHO data. Iron excess is a dangerous clinical disease as well as iron deficiency. Thus, the measurement of blood iron level is of great importance in terms of medicine. To diagnose diseases related to iron levels in the body, continuous, rapid and sensitive systems are essential for the monitoring of key parameters. Biosensors, which consist of a combination of a biological recognition element and a suitable transducer, are among the tools that provide these systems. This study aims to develop a voltammetric biosensor by using hydrogen peroxidase (HRP) enzyme immobilized to the bioactive layer for the measurement of serum iron amount. The bioactive layer was prepared by immobilizing HRP, Bovine Serum albümin (BSA), gelatin and glutaraldehyde on the gold electrode with UV light. To ensure the separation of Fe3+ in the serum from the transferrin, acetate buffer having a pH of 5.0 was preferred. Hydroxylamine hydrochloride was then used to reduce the Fe3+ to Fe2+. Fe2+ which is produced as a result of the reduction was measured by the reaction of hydrogen peroxidase enzyme. In the optimization of the bioactive layer, the amount of BSA was 30 mg, the percentage of glutaraldehyde was 3% and the amount of gelatin was 67.5 mg. In determining the optimum working conditions, the concentration of H2O2 at the concentration of pH 5.0 and 200 mM acetate buffer was determined as 50 mg/dL, while the scanning rate was determined as 0.06 V/s and the temperature was 40 ° C. In the characterization studies, it was determined that linear results were obtained for ferric (Fe3+) iron in the range of 25-200 µg/dL. In studies using ferric (Fe3+) iron concentration of 200 µg/dL for reproducibility (n=10), standard deviation (S.S) = ± 14.35 and % coefficient of variation (V.K) = 7.296 Determination of iron was carried out in biological fluid (in blood) by enzyme electrode. Then, iron was determined in a biological fluid (blood) by enzyme electrode and r: 0.865 and P˂0.05 positive correlation were observed in the comparison study. These results showed that the developed biosensor was a reliable method in serum iron analysis.