Poly(3,4-ethylenedioxythiophene)
nanotubes (PEDOT-NTs) were electrochemically
synthesized onto a stainless steel mesh electrode followed by one-pot
electrodeposition of gold nanoparticles (AuNPs) at the nanotubular
surface. The hybrid nanomaterial has shown remarkable electrochemical
properties with the diminishment of the charge transfer resistance
besides the possibility of further electrode modification by the thiol
bonding at the AuNPs. The modified electrodes were deeply characterized
by electrochemical techniques, in special by electrochemical impedance
spectroscopy, which provides valuable information about the interfacial
processes. The morphology of the nanomaterial was characterized by
scanning electron microscopy and transmission electron microscopy
images. The biosensing properties were evaluated through the avidin/biotin
pair. The methodology of construction of the biosensor was further
adapted to explore a cancer biomarker detection, the folate binding
protein (FBP), which presented high sensitivity with a limit of detection
of 4.5 pmol L–1, one of the lowest found in literature.
Also, the hybrid material was used in the development of supercapacitors,
the inclusion of AuNPs provided a remarkable durability of the PEDOT-NTs
modified electrodes presenting long cycling stability (over 3000 cycles)
and high energy density, compared with bare PEDOT nanotubes modified
electrodes.