  Glucose biosensors play an important role in the diagnosis and continued
monitoring of the disease, diabetes mellitus. This report proposes the
development of a novel enzymatic electrochemical glucose biosensor based on
TiO$_2$ nanotubes modified by AgO and Prussian blue (PB) nanoparticles (NPs),
which has an additional advantage of possessing antimicrobial properties for
implantable biosensor applications. In this study, we developed two high
performance glucose biosensors based on the immobilization of glucose oxidase
(GOx) onto Prussian blue (PB) modified TiO$_2$ nanotube arrays functionalized
by Au and AgO NPs. AgO-deposited TiO$_2$ nanotubes were synthesized through an
electrochemical anodization process followed by Ag electroplating process in
the same electrolyte. Deposition of PB particles was performed from an acidic
ferricyanide solution. The surface morphology and elemental composition of the
two fabricated biosensors were investigated by scanning electron microscopy
(SEM) and energy-dispersive X-ray spectroscopy (EDS) which indicate the
successful deposition of Au and AgO nanoparticles as well as PB nanocrystals.
Cyclic voltammetry and chronoamperometry were used to investigate the
performance of the modified electrochemical biosensors. The results show that
the developed electrochemical biosensors display excellent properties in terms
of electron transmission, low detection limit as well as high stability for the
determination of glucose. Under the optimized conditions, the amperometric
response shows a linear dependence on the glucose concentration to a detection
limit down to 4.91 $\mu$M with sensitivity of 185.1 mA M$^{-1}$ cm$^{-2]$ in Au
modified biosensor and detection limit of 58.7 $\mu$M with 29.1 mA M$^{-1}$
cm$^{-2]$ sensitivity in AgO modified biosensor.
