Evaluating the Diffusion Coefficient of Dopamine at the Cell Surface During Amperometric Detection: Disk vs Ring Microelectrodes
Artikel i vetenskaplig tidskrift, 2013

During exocytosis, small quantities of neurotransmitters are released by the cell. These neurotransmitters can be detected quantitatively using electrochemical methods, principally with disk carbon fiber micro-electrode amperometry. An exocytotic event then results in the recording of a current peak whose characteristic features are directly related to the mechanisms of exocytosis. We have compared two exocytotic peak populations obtained from PC12 cells with a disk carbon fiber microelectrode and with a pyrolyzed carbon ring microelectrode array, with a 500 nm ring thickness. The specific shape of the ring electrode allows for precise analysis of diffusion processes at the vicinity of the cell membrane. Peaks obtained with a ring microelectrode array show a distorted average shape, owing to increased diffusion pathways. This result has been used to evaluate the diffusion coefficient of dopamine at the surface of a cell, which is up to an order of magnitude smaller than that measured in free buffer. The lower rate of diffusion is discussed as resulting from interactions with the glycocalyx.

Författare

R. Trouillon

Göteborgs universitet

Y. Q. Lin

Göteborgs universitet

Lisa Mellander

Göteborgs universitet

Jacqueline Keighron

Chalmers, Kemi- och bioteknik, Analytisk kemi

Andrew Ewing

Chalmers, Kemi- och bioteknik, Analytisk kemi

Analytical Chemistry

0003-2700 (ISSN) 1520-6882 (eISSN)

Vol. 85 13 6421-6428

Ämneskategorier

Analytisk kemi

DOI

10.1021/ac400965d