Biomedical Engineering Reference
In-Depth Information
12.2
General Aspects of Prussian Blue and Other
Hexacyanoferrates
12.2.1 Overview
PB can be considered as the oldest known hexacyanometallate compound,
and has attracted the attention of many scientists seeking an understanding
of its formation, composition, structure and physical properties. h e link-
ing of two dif erent metal ions by the cyanide ligand is the basis of these
properties. In fact, the question of cyanide-isocyanide isomerism is as old
as the discussion of its structure [13, 14], and since then the electronic
interactions between two metals across a cyanide bridge have proven to be
a fertile area of research [11, 15-18].
12.2.2
Chemical and Structure of Prussian Blue and Its
Analogues
h e cyanide ligand (CN
-
) is a reactive ligand in important organometallic
catalytic reactions, and is an ancillary ligand in coordination and bioinorganic
chemistry. Like carbon monoxide, the cyanide ion can function as a π-acid
ligand, but because of its negative charge, the cyanide ion can also form strong
σ-bonds. h is behavior allows CN
-
to stabilize both high and low oxidation
Glucose
Gluconolactone
Glucose oxidase
(GOx)
O
2
H
2
O
2
OH
-
Prussian Blue (PB)
Transducer
Figure 12.2
Detection scheme for a glucose biosensor based on a Prussian Blue (PB)
modii ed electrode. Glucose is converted to gluconolactone, catalyzed by glucose oxidase
(GOx) immobilized on the electrode surface. Secondary to this reaction is the production
of hydrogen peroxide that can be reduced amperometrically at low applied overpotentials,
electrocatalyzed by the PB.
