Amperometric biosensor based on Prussian Blue nanoparticle-modified screen-printed electrode for estimation of glucose-6-phosphate

Glucose-6-phosphate (G6P) plays an important role in carbohydrate metabolism of all living organisms. Compared with the conventional analytical methods available for estimation of G6P, the biosensors having relative simplicity, specificity, low cost, and fast response time are a promising alternative. We have reported a G6P biosensor based on screen-printed electrode using Prussian Blue (PB) nanoparticles and enzymes, glucose-6-phosphate dehydrogenase, and glutathione reductase. The PB nanoparticles acted as a mediator and thereby enhanced the rate of electron transfer in a bienzymatic reaction. The Fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy study confirmed the formation of PB, whereas atomic force microscopy revealed that PB nanoparticles were approximately 25 to 30 nm in diameter. Various optimization studies, such as pH, enzyme, and cofactor loading, were conducted to obtain maximum amperometric responses for G6P measurement. The developed G6P biosensor showed a broad linear response in the range of 0.01 to 1.25 mM, with a detection limit of 2.3 mu M and sensitivity of 63.3 mu A/mM at a signal-to-noise ratio of 3 within 15 s at an applied working potential of -100 mV. The proposed G6P biosensor also exhibited good stability and excellent anti-interference ability, and it worked well for serum samples. (C) 2013 Elsevier Inc. All rights reserved.