  Fabrication of a highly sensitive non-enzymatic electrochemical sensor for
the detection of cholesterol is a challenging issue due to its low redox
activity. In the present study, the electrochemical response of a novel
combination of metal oxides has been explored. NiO/CuO nanocomposite was
fabricated by electrospinning method and its morphology and structural
characteristics were studied using scanning electron microscopy, EDX and X-ray
diffraction techniques. Electrochemical studies revealed that the NiO/CuO/GC
electrode poses a linear detection range between 0.8 to 6.5 mM, low detection
limit of 5.9 microM and a sensitivity of 10.27 microA.mM-1 .cm-2 in the neutral
buffer solution. The fabricated electrode has a response time of 3 seconds and
a good ability to discriminate interfering species. Moreover, the nanocomposite
electrode exhibited high stability as well as the other favorable factors,
makes it an effective sensor for the detection of cholesterol. In addition,
cyclic voltammetry experiments showed that the current response of NiO/GCE is
approximately 30 % of the NiO/CuO/GCE response, suggesting that the
nanocomposite has a greater electrocatalytic activity towards cholesterol
oxidation than NiO nanofibers. NiO/GCE results showed the sensitivity of 2.5
microA.mM-1 .cm-2 , response time of 2 seconds and a limited stability over
three-week time span.
