Neurotransmitter detection by enzyme-immobilized CNT-FET

• Published in: Current applied physics Vol. 9; no. 1; pp. S25 - S28
• Main Authors: Lee, G.J., Lim, J.E., Park, J.H., Choi, S.K., Hong, S., Park, H.K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2009; 한국물리학회
• Subjects: Carbon nanotube; Glutamate; In vivo detection; Real time monitoring; 물리학; Carbon nanotube; In vivo detection; Real time monitoring; Glutamate; 87.83.+a
• ISSN: 1567-1739; 1878-1675
• DOI: 10.1016/j.cap.2008.08.031

Glutamate is the principal excitatory neurotransmitter in the brain, and its excessive release plays a key role in neuronal death associated with a wide range of neural disorders. Real time monitoring of extracellular glutamate levels would be very helpful in understanding the excitotoxic process of neurotransmitters, as well as brain injury during or after surgery.
In order to detect
l-glutamate, we immobilized
l-glutamate oxidase (GLOD) on carbon nanotube (CNT) network junctions by a non-covalent functionalized method to preserve their electronic characteristics. After immobilizing GLOD on the CNT network, the excess reactive groups of linker molecule remaining on its surface were deactivated and blocked by ethanolamine. The electrical property of the GLOD-immobilized CNT network transistor was characterized as source–drain current that depended on liquid gate voltage. From the changes in the
I
sd vs.
V
g plot about the CNT network transistor before and after the immobilization of GLOD, we confirmed that GLOD immobilization decreased the conductance of CNT network junctions, regardless of the sign on the net charge in the protein. The real time electronic response of the GLOD-coated CNT network transistor was conducted with a glutamate standard solution
in vitro and the 11 vessel occlusion (11VO) rat model
in vivo. The ultrahigh sensitivity, selectivity, and fast response time of GLOD-immobilized CNT-FET could provide great potential for the real time electronic detection of extracellular glutamate levels in the brain.