A sensitive electrochemical method for the detection of avian influenza virus (AIV) H5N1 gene sequence
using a DNA aptamer immobilized onto a hybrid nanomaterial-modified electrode was developed. To
enhance the selectivity and sensitivity, the modified electrode was assembled with multi-wall carbon
nanotubes (MWNT), polypyrrole nanowires (PPNWs) and gold nanoparticles (GNPs). This electrode
offered a porous structure with a large effective surface area, highly electrocatalytic activities and electronic
conductivity. Therefore, the amount of DNA aptamer immobilized onto the electrode was increased
while the accessibility of the detection target was maintained. The biosensor is based on the hybridization
and preferred orientation of a DNA aptamer immobilized onto a modified electrode surface with its
target (H5N1 specific sequence) present in solution. It is selective for the H5N1 specific sequence, and the
signal of the indicator was approximately linear to log(concentration) of the H5N1 specific sequence from
5.0
×
10−12 to 1.0
×
10−9M (R = 0.9863) with a detection limit of 4.3
×
10−13 M. These studies showed that
the new hybrid nanomaterial (MWNT/PPNWs/GNPs) and the DNA aptamer could be used to fabricate an
electrochemical biosensor for gene sequence detection. Furthermore, this design strategy is expected to
have extensive applications in other biosensors.