An amperometric urea bisosensor based on covalent immobilization of urease on N-2 incorporated diamond nanowire electrode

作者：Shalini Jayakumar; Sankaran Kamatchi Jothiramalingam; Lee Chi Young^*; Tai Nyan Hwa; Lin I Nan

来源：Biosensors and Bioelectronics, 2014, 56: 64-70.

DOI：10.1016/j.bios.2013.11.071

• N-2 incorporated diamond nanowire
• Urs-GLDH/N-DNW
• Urea
• Cyclic voltammetry
• Electrochemical impedance spectrsocopy
• Amperometry

N-2 incorporated diamond nanowire (N-DNW) film electrochemical biosensor has utilized for the quantitative determination of urea in aqueous solution and urine sample. N-DNW electrode is wet-chemically cleaned (oxidation) by boiling in a mixture of H2SO4 and HNO3 (3:1) at 200 degrees C for 2 h to remove graphite. Urease (Urs) and glutamate dehydrogenase (GLDH) are covalently attached to the oxidized N-DNW electrode by activating the COOH group of N-DNW using ethyl(dimethylaminopropyl) carbodiimide as the coupling agent and N-hydroxysuccinimide as activator. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy data reveal that carboxylic and hydroxyl functionalized nature of N-DNW electrodes Urs-GLDH immobilized N-DNW (Urs-GLDH/N-DNW) has been successfully utilized in urea biosensor which exhibits good performance in sensitivity (6.18 mu A/mg dL/cm(2)), stability (similar to 1 month), reproducibility, lower detection limit (3.87 mg/dL) and fast response time ( > 10 s). Urs-GLDH/N-DNVV also exhibits electrochemical response when tested for different concentration of human urine in buffer solution (from 1:9 to 4:6). In addition, Urs-GLDH/N-DNW bioelectrode retains 80% of its initial enzyme activity for < 1 month, when stored at 4-6 degrees C in a refrigerator.

• 出版日期2014-6-15
• 单位清华大学