Elektroeğirme ile hazırlanan nanofiber membranlara ürikaz immobilizasyonu ve voltametrik ürik asit biyosensörü olarak kullanımı

Uric acid (UA) is clinically used as a marker of various diseases, especially gout and hyperuricemia. Therefore, precise measurement of biological samples such as serum and food samples is crucial. Uricase (urate oxidase, E.C.1.7.3.3, UOx) is the enzyme responsible for the oxidation of UA to allantoin in the body, and it is widely used especially in measuring UA level in vitro. In practice, there are colorimetric, chromatographic, spectrophotometric and biosensor-based methods for UA determination. However, a crucial need for determination of UA is exist, especially the creation of rapid results, selective and easy-to-use systems. In this study, the preparation of screen-printed electrodes containing membranes prepared by electrospinning, immobilization of UOx enzyme and its use as an voltammetric UA biosensor for the selective and sensitive determination of UA are available. In this context, polycaprolactone (PCL, 10%) was used in the membrane prepared by electrospinning due to its mechanical strength, and polyethyleneimine containing amine group (PEI, 7.5%) was used for the immobilization of the enzyme. Quantum Dot Screen Printed Electrode (QD - SPCE) containing two different membranes was prepared. One of them is PCL/PEI /UOx /QD – SPCE, the other is PCL/PEI/UOx/MB/QD–SPCE supplemented with methylene blue (MB). The prepared membranes were structurally characterized by FTIR, EDX and XRD, morphologically by SEM and voltammetric by water contact angle. Standardization in was performed by DPV (Differential Pulse Voltammetry) technique for UA concentration between 5 and 52 µM in PBS pH 7.4. Results were determined as LOD: 3.9619 ± 0.588 µM (R 2 = 0.9947) for UOx/QD–SPCE, while LOD: 1.8598 ± 0.2345 µM (R 2 = 0.9988) for UOx/MB/QD–SPCE. The 4-week stability results showed the change in current for UOx/QD–SPCE and UOx/MB/QD–SPCE to be 92% and 87%, respectively. In addition, in the mixed interference test remaining current ratios for UA were 95% and 82% for the UOx/QD–SPCE and UOx/MB/QD–SPCE electrodes, respectively. As a result, it has been determined that the two prepared biosensor systems have comparable measurement qualities with the sensors in the literature in UA measurement.