Biology Reference
In-Depth Information
is from a combination of a higher nanoparticle loading and the use
of DPV forquantitation,instead ofLSV.
8.7 Areas for Further Research
It is hoped that this chapter has transmitted two general points:
that it is relatively straightforward to adapt latex colloids for use
as electrochemical labels, and that very little has been done in this
field up to now. Some possible further directions for research are as
follows:
1. Increasing the nanoparticle loading on the latex spheres via the
autocatalytic metal deposition previously described [35, 36].
2. Increasing the nanoparticle loading on the hollow capsules by
finding a way to load the central volume of the capsules, rather
than just the capsule walls.
3. Applying either latex or capsule labels to multianalyte detection
by preparing labels loaded withdifferent metals.
4. Designing a cell arrangement to reduce the electrolyte volume
needed for ASV. This would increase sensitivity by increasing the
concentration of the liberated metal ions.
5. Extending the use of latex-based labels to the analysis of real
samples.
It should also be noted that many of the previously reported latex
l-b-l modifications have described the deposition of layers of redox
enzymes [55, 84, 85], and hence these structures could also be
used as labels. Hollow capsules have also been used to entrap
enzymes [101]. While enzyme stability can sometimes be an issue,
thesensitivityprovidedbyenzymesisoftenverygood.Forexample,
l-b-l deposition of alkaline phosphatase onto carbon nanotubes
resulted in electrochemical DNA sensing down to 5.4 aM [132]. In
comparison with a nanotube, a latex sphere of diameter
∼
0.5
μ
m
presentsaverymuchlargersurfaceareaforimmobilization.Finally,
virtually everything stated in this chapter regarding DNA labeling
can equallybeapplied to thelabeling of antibodies.
