Measurement of Glutamate Using Biosensor Based on Vertically Aligned Carbon Nanotubes

A sensitive glutamate biosensor is prepared based on glutamate dehydrogenase/vertically aligned carbon nanotubes (GLDH, VACNTs). Vertically aligned carbon nanotubes were grown on a silicon substrate by Direct Current Plasma Enhanced Chemical Vapor Deposition (DC-PECVD) method. Glutamate dehydrogenase covalently attached on tip of VACNTs. The electrochemical performance of the electrode for detection of glutamate was investigated by cyclic and differential pulse voltammetry. The linear calibration curve of the concentration of glutamate versus peak current is investigated in a wide range of 0.1–500 mM. The mediator-less biosensor has a low detection limit of 57 nM and two linearranges of 0.1–20 mM with a sensitivity of 0.976 mA/mM cm2 and 20–300 mM with a sensitivity of 0.182 mA/mM. cm2. The effects of the other biological compounds on the voltammetric behavior of the prepared biosensor and its response stability are investigated. The results are demonstrated that the GLDH/VACNTs electrode even without electron mediator is a suitable basic electrode for detection of glutamate.