A Micro-Platinum Wire Biosensor for Fast and Selective Detection of Alanine Aminotransferase

• Published in: Sensors (Basel, Switzerland) Vol. 16; no. 6; p. 767
• Main Authors: Thuy, Tran Nguyen Thanh, Tseng, Tina T-C
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26.05.2016; MDPI
• Subjects: Acids; Alanine; alanine aminotransferase; Alanine Transaminase - analysis; Alanine Transaminase - metabolism; amperometric; Biosensing Techniques - methods; biosensor; Biosensors; Cellulose acetate; Chromatography; Constants; Dehydrogenases; Dopamine; Electrical measurements; Electrodes; Enzymes; glutamate oxidase; Liver diseases; microelectrode; Oxidase; Platinum - chemistry; Polypyrroles; Sensors; Voltammetry; Wire; alanine aminotransferase; microelectrode; biosensor; glutamate oxidase; amperometric
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s16060767

In this study, a miniaturized biosensor based on permselective polymer layers (overoxidized polypyrrole (Ppy) and Nafion(®)) modified and enzyme (glutamate oxidase (GlutOx)) immobilized micro-platinum wire electrode for the detection of alanine aminotransferase (ALT) was fabricated. The proposed ALT biosensor was measured electrochemically by constant potential amperometry at +0.7 V vs. Ag/AgCl. The ALT biosensor provides fast response time (~5 s) and superior selectivity towards ALT against both negatively and positively charged species (e.g., ascorbic acid (AA) and dopamine (DA), respectively). The detection range of the ALT biosensor is found to be 10-900 U/L which covers the range of normal ALT levels presented in the serum and the detection limit and sensitivity are found to be 8.48 U/L and 0.059 nA/(U/L·mm²) (N = 10), respectively. We also found that one-day storage of the ALT biosensor at -20 °C right after the sensor being fabricated can enhance the sensor sensitivity (1.74 times higher than that of the sensor stored at 4 °C). The ALT biosensor is stable after eight weeks of storage at -20 °C. The sensor was tested in spiked ALT samples (ALT activities: 20, 200, 400, and 900 U/L) and reasonable recoveries (70%~107%) were obtained.