Immobilization of Bilirubin Oxidase Nanoparticles onto Gold Electrode for Amperometric Detection of Serum Bilirubin

Abstract

‘Bilirubin oxidase nanoparticles’ (BOxNPs) were prepared from commercial bilirubin oxidase by using the ‘desolvation method’. An amperometric bilirubin biosensor was developed by immobilizing BOxNPs onto an Au electrode. The morphology in terms of size and shape of BOxNPs aggregates was studied by “transmission electron microscopy (TEM)”, “dynamic light scattering (DLS)” and “Scanning electron microscopy (SEM)” which were utilized to characterize BOxNPs/Au electrode. BOxNPs/Au electrode demonstrated an optimum response time (1s), pH (8.5), and temperature (35°C) when polarized at a potential (+0.3 V). The lowest ‘detection limit’ (0.01 µM) was calculated by selecting a concentration range from 0.01 to 1000 µM for bilirubin. BOxNPs/Au electrode was employed to detect total serum bilirubin in healthy people and people suffering from jaundice. When the electrode was stored at a low temperature in sodium phosphate buffer (0.1 M, pH 7.0), it retained 50% of its original activity with storage stability of 150 days.