Nitric oxide (NO) electrochemical sensors - Electrochemical Sensors, Biosensors and Their Biomedical Applications - page 17

m Acc V

10.0 kV

Spol
5.0

Dot
GSE

WD
21.2

Exp
1

200

Magn
100x

0.9 Torr

(a)

HUVEC cells

Buffer

pt

17 m

active electrode tip
insulated base

23 m

(b)

microelectrode array

FIGURE 1.8 (a) A representative SEM image of the microelectrode array and (b) a schematic represen-
tation of the experimental setup. (Reprinted with permission from Elsevier Publishing [124].)

into the region of the trabecular meshwork and NO monitored as a function of epine-
phrine concentration. This study found that NO generation increased as a function of
epinephrine addition resulting in a reduction of intraocular pressure. This fi nding is
important for shedding light on treatments for patients with primary open-angle glau-
coma. Researchers such as Akeo and Amaki have used a Pt/Ir electrode, coated with
NO selective membranes, for the determination of what effects L-DOPA has on eyes
[80, 81].
Because NO is a diffusible messenger molecule in the brain the measurement
of NO concentration in vitro is quite important to understand its action. In order to
accomplish this general goal, Gerhardt's group recently developed an 8 m diameter

carbon fi ber electrode coated with Nafi on and o -phenylenediamine [50]. Nafi on was
added to the electrode surface by dipping the electrode into a 5% solution followed
by drying for 10 min at 170ºC followed by o -phenylenediamine electropolymerization
on the electrode by holding the potential at

µ

0.9 V vs Ag/AgCl reference electrode.
These electrodes were then inserted into the CA1 region of the hippocampus, from