Biomedical Engineering Reference
In-Depth Information
adsorption. In one determination of specii c blood cell, HRP-labelled anti-
blood group an IgM was utilized in the ELISA assay. Based on electrode
working on screen-printed graphite, an immunosensor allowed for the
rapid estimation and calculation of fatty acid-binding protein (FABP) in
neat plasma samples was designed by Schreiber
et al.
[62]. h e antibodies
that had been captured were bound to the electrode surface by adsorp-
tion, conduction and trapped FABP from the plasma samples. A second
monoclonal antibody had completed the sandwich by conjugating with
alkaline phosphatase. h e enzyme has been converted to
p
-aminophenol
from
p
-aminophenyl phosphate which was then detected amperometri-
cally. Ivnitski and Rishpon [63], developed a one-step that is separation of
free enzyme immune-sensor in the reaction. h e bio-sensor consisted of
an antibody electrode which is very important for reaction. h e immune-
sensor combines enzyme channelling immunoassay, cyclic regeneration of
an enzyme (peroxidase) substrate at the polymer (polyethylenenimine)/
electrode interface, accumulation of redox mediators, for controlling of the
hydrodynamic conditions at the interface of the antibody electrode in the
electrochemical reaction. h e immunological reactions were monitored
electrochemically every time and at every moment.
Biosensors reported for urea detection are specii cally based on urease
(Ur) which is ot en present in most biological systems as known [64-70].
Ur catalyzes the decomposition of urea into ammonium ions (NH
4
+
) and
hydrogen bicarbonate. NH
4
+
ions are known to be unstable and can be
easily disperse in the environment eventually. Keeping the condition in
mind, glutamate dehydrogenase (GLDH) along with Ur has been specii -
cally utilized for urea detection as GLDH immediately catalyzes the reac-
tion between α- ketoglutarate (α-KG) ,NH
4
+
and nicotinamide adenine
di-nucleotide (NADH) to produce L-glutamate [68-70] and NAD
+.
Metal oxide nanoparticles-chitosan (CH) which is on based hybrid
composites has attracted much interest for the development of a desired
biosensor in biological system [69-71]. Metal oxide nanoparticles such as
iron oxide (Fe
3
O
4
) [72-74], zinc oxide (ZnO) [75, 76], cerium oxide (CeO
2
)
[77, 78], etc. have been suggested as promising matrices for desired bio-
molecules to be immobilzed. h ese nanomaterials exhibit and enhances
large surface to volume ratio, high catalytic ei ciency, high surface reac-
tion activity and strong adsorption ability that can be helpful to obtain
improved sensitivity, specii city and stability of a biosensor. Moreover,
nanoparticles have a unique ability to promote and establish fast electron
transfer between the active site of an enzyme and electrode. Among vari-
ous metal oxide nanoparticles noted such as Fe
3
O
4
nanoparticles due to
strong super paramagnetic behaviour, biocompatibility and low toxicity
