Nanochemistry and biotechnology

Amperometric biosensor modified with m-PhD/SiO2-GNPs-GOx for determination of glucose in wine
Shkotova L.V.1, Kovalchuk V.V.2, Dzyadevych S.V.1,2
1 Laboratory of Biomolecular Electronics, Institute of Molecular Biology and Genetics, NAS of Ukraine, 150, Akademika Zabolotnogo Str., Kyiv-03680, Ukraine.
E-mail: luda_shkotova@yahoo.com
2 Institute of High Technologies, Taras Shevchenko National University of Kyiv
2, korp.5, Pr. Akademika Hlushkova, Kyiv-03022, Ukraine.

The amperometric biosensor based on glucose oxidase immobilized in silica-gold nanoparticles gel at platinum disc electrodes was developed for glucose determination. The surface of working electrodes was modified with nanocomposite film (SiO2-GNPs-GOx) to increase the biosensor sensitivity. It was shown that the modification resulted in decreasing working potential and 5-fold higher sensitivity (Fig. 1, A, curve 2). An additional layer of electrochemically polymerized m-phenylenediamine was used to raise the selectivity for glucose over the actual interferents.
          
  A					B
A- Calibration curves of glucose biosensor based on platinum disc electrodes: 1– non-modified electrodes; 2 – electrodes modified with (SiO2-GNPs-GOx) nanocomposite film. B – Glucose concentration measured in wine samples by developed biosensor (black bar) and by spectrophotometric method (grey bar). Measurement conditions: 0.1M phosphate buffer, pH 7.2, applied potential – 0.4 V vs. Ag/AgCl.
The optimized biosensor has shown the following characteristics: the linear range for glucose determination – 0.05÷4 мМ, sensitivity of 123.75 µА•М-1•см-2 and detection limit of 0.1 µМ. The biosensor response does not depend on actual interferents. The correlation coefficient of data obtained using the biosensor and spectrophotometric method is 0.9983 (Fig.1, B). The biosensor response after 100-day storage at 4ºC was 65% of initial value.