Amperometric Detection of Single Vesicle Acetylcholine Release Events from an Artificial Cell
Artikel i vetenskaplig tidskrift, 2015

Acetylcholine is a highly abundant nonelectroactive neurotransmitter in the mammalian central nervous system. Neurochemical release occurs on the millisecond time scale, requiring a fast, sensitive sensor such as an enzymatic amperometric electrode. Typically, the enzyme used for enzymatic electrochemical sensors is applied in excess to maximize signal. Here, in addition to sensitivity, we have also sought to maximize temporal resolution, by designing a sensor that is sensitive enough to work at near monolayer enzyme coverage. Reducing the enzyme layer thickness increases sensor temporal resolution by decreasing the distance and reducing the diffusion time for the enzyme product to travel to the sensor surface for detection. In this instance, the sensor consists of electrodeposited gold nanoparticle modified carbon fiber microelectrodes (CFMEs). Enzymes often are sensitive to curvature upon surface adsorption; thus, it was important to deposit discrete nanoparticles to maintain enzyme activity while depositing as much gold as possible to maximize enzyme coverage. To further enhance sensitivity, the enzymes acetylcholinesterase (AChE) and choline oxidase (ChO) were immobilized onto the gold nanoparticles at the previously determined optimal ratio (1:10 AChE/ChO) for most efficient sequential enzymatic activity. This optimization approach has enabled the rapid detection to temporally resolve single vesicle acetylcholine release from an artificial cell. The sensor described is a significant advancement in that it allows for the recording of acetylcholine release on the order of the time scale for neurochemical release in secretory cells.

enzymes

artificial cell

Biosensor

acetylcholine

amperometry

exocytosis

gold nanoparticles

Författare

Jacqueline Keighron

Kemi och kemiteknik, Kemi och biokemi, Analytisk kemi

Joakim Wigström

Kemi och kemiteknik, Kemi och biokemi, Analytisk kemi

Michael Kurczy

Kemi och kemiteknik, Kemi och biokemi, Analytisk kemi

Jenny Bergman

Göteborgs universitet

Yuanmo Wang

Kemi och kemiteknik, Kemi och biokemi, Analytisk kemi

Ann-Sofie Cans

Kemi och kemiteknik, Kemi och biokemi, Analytisk kemi

ACS Chemical Neuroscience

1948-7193 (ISSN)

Vol. 6 181-188

Ämneskategorier

Biokemi och molekylärbiologi

DOI

10.1021/cn5002667

PubMed

25565357