Biomedical Engineering Reference
In-Depth Information
and allowed the detection of a very low level of target DNA.
86
This behaviour
was conirmed by the detection of DNA segments related to the BRCA1 breast
cancer gene, where the signal ampliication led to the detection of extremely
low target concentrations in solution (100 ppt).
Also, Yao
et al.
proposed CPSA with a CNT-modiied electrode as a new
methodology to detect human breast cancer (MCF-7) cells and obtain a
quantitative response. The authors evaluated the effect of 5-Fluorouracil (5-
FU), a well-known anticancer drug, on potentiometric signals. Cell cultures -
treated and not treated by 5-FU - were studied, and it emerged that the higher
was the anticancer drug dose, the lower was the relative potentiometric signal
response.
87
The same group adopted another technique for cytosensing:
the quartz crystal microbalance (QCM). They modiied a Au electrode with
chitosan (known for its high biocompatibility and low mechanical properties)
and MWCNTs, which can act as illers to enhance mechanical strength.
88
The
so-obtained electrode has been proved to present a surface favourable for cell
loading and adhesion and to work on the QCM. These measurements were
accompanied by electrochemical analyses (voltammetry and potentiometry)
and a MTT test, demonstrating the possibility of monitoring the presence of
breast cancer cells by their adhesion on the modiied electrode.
a
b
Figure 3.16
(a) A QCM set-up; (b) a modiied electrode with attached cells.
Abbreviations
: GCE, glass carbon electrode; G
R
, guanidine, reduced form; G
O
, guanidine,
oxidised form.
Chen
et al.
studied the possibility of selecting the most effective
anticancer therapeutic agents by means of the electrochemical behaviour of
leukemia cells (K562). The authors modiied a glassy carbon electrode with
MWCNTs and studied its voltammetric response in the presence of different
antitumour agents (5-FU, mitocycin C, adriamycin and vincristine). The cells
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