Место издания:Military Publishing House Sofia, Bulgaria
Первая страница:68
Последняя страница:81
Аннотация:A tyrosinase-based phenol biosensors were formed via layer-by-layer (LBL) approach to deposit poly(dimethyldiallylammonium chloride) (PDDA) and tyrosinase onto graphite-based substrates, followed by optional glutaraldehyde (GA) crosslinking. The good analytical parameters of phenol detection thogether with low detection limit enabled phenol measurements in highly diluted blood samples, which also minimized interference from extraneous (non-analyte) substances in blood (e.g., adrenaline, ascorbate, glucose, L-tyrosine, and urate). Applicability of the biosensor to analysis of carboxylesterase (CaE), paraofonase 1 (PON1) and neuropathy target esterase (NTE) activities in mouse and human blood was demonstrated. Parallel biosensor and spectrophotometric CaE analyses were carried out 1 h after intraperitoneal injection of mice with the model dialkylphosphate, (C2H5O)2P(O)OCH(CF3)2 (DEHFPP). Dose-related inhibition of CaE activity was observed, yielding ED50 values [mean (95% CI) (n)] of 25.5 (23.2, 28.0) mg/kg (6) and 21.1 mg/kg (18.9, 23.5) (4) for spectrophotometric and electrochemical assays, respectively. Although the ED50 values were significantly different from each other (p < 0.007), excellent correlation between biosensor and spectrophotometric measurements was found (r = 0.99), indicating that the differences between the two methods are systematic and providing validation of the biosensor assay.