Biomedical Engineering Reference
In-Depth Information
element with a thin i lm of PB, allowing the detection of the H
2
O
2
gener-
ated enzymatically by GOx at a potential close to 0 V
vs
SCE. h at year,
Jaf ari and Turner [35] presented a patent in the UK (later extended to an
international patent) for an amperometric biosensor for the determination
of blood glucose using a PB-modii ed graphite electrode [36]. At er that,
PB-modii ed biosensors for other molecules such as lactate, sucrose, galac-
tose, cholesterol, choline, oxalate, lysine, acetylcholine, ethanol, glutamate
and NADH have been reported in the literature [11, 12].
Although the i rst PB-modii ed transducers were carbon paste, glassy
carbon and platinum electrodes, recently screen-printed electrodes (SPEs)
have been used because they are inexpensive, simple and quick to prepare,
versatile, and are the most economical method for large-scale production
and for the assembling of spot-test kits for clinical and environmental
analysis. First reports were based on the chemical synthesis of PB and sub-
sequent bulk modii cation of the carbon ink by PB microparticles [37] or
the in-situ modii cation of glassy carbon or graphite powder with PB [38].
Another method, proposed by Ricci
et al.
[39], involved the direct chemi-
cal synthesis of PB onto SPEs, by placing a drop of precursor solution onto
the working electrode area. An important advance in the context of the
electro-deposition of PB (and other hexacyanoferrates) was the addition a
cationic surfactant such as CTAB (acetyl-trimethyl-ammonium-bromide),
BZTC (benzethonium chloride) or CPC (cetylpyridinium chloride). With
this approach, a signii cantly enhanced i lm growth, ei cient charge trans-
fer kinetics, and high stability and sensitivity toward H
2
O
2
detection have
been reported for SPEs [16, 17, 40, 41].
Nowadays, Dropsens SL (Oviedo, Spain) commercializes screen-
printed carbon electrodes (SPCEs) modii ed with PB (
Figure 12.5
),
Counter
Electrode
(Carbon)
Working
Electrode
(Prussian
Blue/Carbon)
C.E.
connection
Reference
Electrode
(Silver)
W.E.
connection
R.E.
connection
5
m
Figure 12.5
h e structure of commercial Prussian Blue-modii ed screen printed electrode
commercialized by Dropsens SA, Spain, including a scanning electron micrograph on the
right
.
