title: Fabrication of sensitive glutamate biosensor based on vertically aligned CNT nanoelectrode array and investigating the effect of CNTs density on the electrode performance.
abstract: In this report, the fabrication of vertically aligned carbon nanotube nanoelectrode array (VACNT-NEA) by photolithography method is presented. Electrochemical impedance spectroscopy as well as cyclic voltammetry was performed to characterize the arrays with respect to different diffusion regimes. The fabricated array illustrated sigmoidal cyclic voltammogram with steady state current dominated by radial diffusion. The fabricated VACNT-NEA and high density VACNTs were employed as electrochemical glutamate biosensors. Glutamate dehydrogenase is covalently attached to the tip of CNTs. The voltammetric biosensor, based on high density VACNTs, exhibits a sensitivity of 0.976 mA mM(-1) cm(-2) in the range of 0.1-20 μM and 0.182 mA mM(-1) cm(-2) in the range of 20-300 μM glutamate with a low detection limit of 57 nM. Using the fabricated VACNT-NEA, the sensitivity increases approximately to a value of 2.2 Am M(-1) cm(-2) in the range of 0.01 to 20 μM and to 0.1 A mM(-1) cm(-2) in the range of 20-300 μM glutamate. Using this electrode, a record of low detection limit of 10 nM was achieved for glutamate. The results prove the efficacy of the fabricated NEA for low cost and highly sensitive enzymatic biosensor with high sensitivity well suited for voltammetric detection of a wide range of clinically important biomarkers.
authors: Institute for Nanoscience and Nanotechnology (INST), Sharif University of Technology, Tehran, Iran.
authors: Azam
authors: A
authors: Gholizadeh
authors: Saeed
authors: S
authors: Shahrokhian
authors: Azam
authors: A
authors: Iraji zad
authors: Shamsoddin
authors: S
authors: Mohajerzadeh
authors: Manouchehr
authors: M
authors: Vosoughi
authors: Sara
authors: S
authors: Darbari
authors: Javad
authors: J
authors: Koohsorkhi
authors: Mahdiyeh
authors: M
authors: Mehran
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation*; D002417:Cattle; D058266:Dielectric Spectroscopy; D004563:Electrochemistry; D004566:Electrodes; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D018698:Glutamic Acid / Q000032:analysis* / Q000737:chemistry; D036103:Nanotechnology / Q000295:instrumentation*; D037742:Nanotubes, Carbon / Q000737:chemistry*
chemical_list: D037742:Nanotubes, Carbon; D018698:Glutamic Acid; D005969:Glutamate Dehydrogenase