Biomedical Engineering Reference
In-Depth Information
17
18
19
Figure 5.12
Possible interaction between MWCNTs, DNA and cyt
c
for the formation
of MWCNT-DNA-cyt
c
biocomposite ilm modiied electrodes. Reproduced from Shie
et al.
38
with permission. See also Colour Insert.
The results of the experiments performed on several electrodes (e.g., glassy
carbon electrode [GCE], gold [Au], indium tin oxide [ITO] and screen-printed
carbon electrode [SPCE]) proved that the deposition of cyt
c
on the MWCNT-
DNA biocomposite ilm was more stable and uniform on Au than on other
electrodes. The presence of both MWCNTs and DNA in the biocomposite ilm
increased the electron transfer rate constant (
K
s
) up to 21% and decreased
the degradation of cyt
c
during the cycling, thus suggesting an effective
approach for the development of voltammetric and amperometric sensors.
The biocomposite ilm also exhibited a promising, enhanced electrocatalytic
activity towards the reduction of halogen oxyanions such as IO
3
−
, BrO
3
−
and
ClO
3
−
and oxidation of biochemical compounds such as ascorbic acid and -
cysteine.
In a very recent article, Zhou
et al.
exploited the solubilising power of
DNA towards CNTs to investigate the complexes formed by the incorporation
of quantum dots (QDs) and provide unique fluorescence properties.
41
DNA
consisted of guanine (G) and thymine (T) repeating units as linkers between
QDs and CNTs, and they provided characteristic bands at Fourier transform
infrared-attenuated total reflectance (FTIR-ATR) spectra (3,182 and 1,630
cm
-1
), correspondent to the stretching and bending modes, respectively, of
the primary aromatic amines of the guanine bases. The same sharp bands
disappeared after amide bonding between carboxyl-QDs and amine-DNA
molecules physisorbed onto SWCNTs
(Fig. 5.13).
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