An electrochemical conducting polymer-based biosensor for Leukocyte esterase and nitrite detection for diagnosing urinary tract infections: A pilot study

Leukocyte esterase (LE) and nitrite ANN') are t iornarkers t_t the diagnosis or minary ,ract infections (UITs). Fast and versatile multi-analyte biosensors are of increasing interest in disease detection. To our knowledge research on the detection of these two markers in clinical samples by using disease-related electrochemical biosensors is rate. In this pilot study, we prepared an electrochemical sensor for detection of LE and HIT, based on LE antibody conjugated to a carboxylic acid-functionalized poly(3,4-ethylenedioxythiophene) (PEDOT-COOH) modified glassy carbon electrode (GCE), namely, LE antibody/Avidin/EDC-NHSREDOT-COOH/GCE, in which PEDOTCOOH as the substrate allows integration with biomolecules (LE antibody and avidin) for selectively recognizing LE and extends the sensing range due to the good electroactivity. The characterization of the electrode was demonstrated by scanning electron microscopy, Fourier-nansforrn infrared spectroscopy, differential pulse voltanuneny, and electrochemical impedance spectroscopy. Under the optimized conditions, the fabricated electrode showed good perforrnance with a linear range of 9.1-131 mu M and 0.2-590 pg L 1, and the limits of detection were 6.2_. mu M and 0.2 pg L 1 for NIT and LE, respectively. Finally, urine specimens were obtained from 13 patients enrolled at Taipei Veterans General Hospital. All mine samples with NIT and LE positive in urine stTips were tested positive by otu work for NIT and LE detection, and samples with negative findings tested negative. Using the device to detect NIT and LE for identifying patients with UTIs, the diagnostic sensitivity and specificity were 100 % and 87.5 /o, respectively. Thus, this biosensor may be a potential alternative to the urine strip test because of its simplicity, rapidity, multi-analyte detection, and high sensitivity. A large-scale study using more diverse samples is warranted to validate its clinical value in assisting UTI diagnosis.