Biomedical Engineering Reference
In-Depth Information
decades in helping to detect glucose in analytical solutions ( Newman and Turner, 2005;
Wilson and Gifford, 2005 ). Electrochemical sensors have been in the forefront in this area
of research ( Wang, 2008 ). Nanomaterials exhibit unique electronic and mechanical pro-
perties; therefore, not surprisingly, there has been considerable work with regard to the
applications of nanomaterials for glucose detection in solutions ( Lu et al., 2006, 2007;
Vamvakaki et al., 2006; Wu et al., 2007a,b; Deng et al., 2008; Jeykumari and Narayan,
2008; Liu et al., 2008a,b; Zhou et al. 2008 ). Katakis and Dominguez (1995) , however, point
out the instabilities associated with the intrinsic nature of the enzymes and the tedious fabri-
cation procedures involved. There is a need to overcome these shortcomings, perhaps by
using nonenzymatic biosensors, which will help eliminate the problems associated with the
use of enzymes.
Thus, considerable effort has been spent on developing nonenzymatic electrodes for glucose
determination ( Vassilyev et al., 1985; Adzic et al., 1989; Sun et al., 2001 ). Liu et al. (2009)
report that the development of nanotechnology has also contributed to this effort by
providing various materials for electrodes, including macroporous platinum film ( Song
et al., 2005 ), ordered platinum arrays ( Yuan et al., 2005 ), nanoporous platinum-palladium
networks ( Wang et al., 2008 ), three-dimensional silver film ( Bai et al., 2008 ), and platinum-
ruthenium nanoparticles (Li et al., 2008). However, even here there is a shortcoming, in spite
of the high electrocatalytic activity exhibited by the precious metal electrodes, due to the
chemisorption of intermediates which subsequently leads to fouling of the electrodes. This
results in poor operational stability. Furthermore, as Liu et al. (2009) emphasize, the high
cost of these precious metals prohibits their use for commercial applications where low cost,
as they correctly point out, is a major requirement.
Liu et al. (2009) report that metal oxide and complex catalysts may be used to modify the
electrodes for the nonenzymatic detection of glucose ( Chen et al., 1993, 2008; Kang et al.,
2007; Ozcan et al., 2008 ). Ni-based materials are a good low-cost catalyst that may be used
for the electrocatalytic oxidation of analytes other than glucose. For example, they have been
used in the electrocatalytic oxidation of carbohydrates ( Reim and Effen, 1986 ; You et al.,
2003; Casella and Gatta, 2001; Ojani et al., 2008 ), insulin ( Salimi et al., 2007 ), aspirin
( McAuley and Wildgoose, 2008 ), and ethanol ( Casella et al., 1993; Wang et al., 2004a,b ).
The nickel-based materials apparently catalyze the oxidation processes via the formation of a
high valent oxyhydroxide species.
Liu et al. (2009) point out that the electrospinning technique has received attention in both
the academic and industrial environments. This is useful, particularly to get nanofibers with
different architectures and compositions. For example, Hou and Reneker (2004) combined
the electrospinning technique with the carbonization process to obtain a novel hierarchical
structure of carbon nanotubes on nanofibers. Electrospinning of three-dimensional nano-
fibrous tubes with controllable architectures has also been reported ( Zhang and Chang, 2008 ).
Search WWH ::




Custom Search