Chinese Journal of Applied Chemistry ›› 2016, Vol. 33 ›› Issue (1): 116-122.DOI: 10.11944/j.issn.1000-0518.2016.01.150239

• Full Papers • Previous Articles    

Bile Acid Sensor Based on Photoelectrochemical Response to Nicotinamide Adenine Dinucleotide

ZHAO Changzhi(),KONG Yanyun,HE Yanyan,ZHANG Zhaoxia   

  1. Shandong Provincial Key Laboratory of Biochemical Analysis,College of Chemistry & Molecular Engineering,Qingdao University of Science & Technology,Qingdao,Shandong 266042,China
  • Received:2015-07-09 Accepted:2015-09-25 Published:2016-01-05 Online:2016-01-05
  • Contact: ZHAO Changzhi
  • Supported by:
    Supported by the Natural Science Foundation of Shandong Province, China(No.2009ZRB01393), and the Open Fund of State Key Laboratory of Electroanaytical Chemistry(No.SKLEAC201106)

Abstract:

Poly(thionine)/multi-walled carbon nanotubes(p-Th/MWNTs) photoelectrode was prepared by electropolymerizing thionine(Th) on the surface of MWNTs-modified ITO electrode. A novel photoelectrochemical bile acid sensor was fabricated by immobilizing 3α-hydroxysteroid dehydrogenase(3α-HSD) on the surface of the photoelectrode. With this photoelectrode as an electron acceptor, and nicotinamide adenine dinucleotide(NADH) from enzymatic reaction as an electron donor, bile acid was determined by the photocurrent from photoelectrochemical effect between p-Th on the photoelectrode and NADH produced in 3α-HSD catalyzed reaction of bile acid. The preparing condition of the photoelectrode, such as MWNTs coating amount, initial concentration of Th and the enzyme loading were optimized. The effects of the electrolyte pH, the concentration of NAD+ and the bias voltage on detecting the substrate were investigated at optimized conditions. The measuring range of bile acid sensor is from 1.80 to 40.0 μmol/L with a sensitivity of 5.86 μA/(mol·L), and the detection limit is estimated to be 0.67 μmol/L. The recovery is in the range of 96%~104% for the determination of cholic acid in sodinm cholate tablets and bile acid in human urine.

Key words: bile acid sensor, photoelectrochemistry, multi-walled carbon nanotubes, thionine, nicotinamide adenine dinucleotide