Enhanced direct electron transfer of redox protein based on multiporous SnO₂ nanofiber-carbon nanotube nanocomposite...

A novel third generation H₂O₂ biosensor is fabricated using multiporous SnO₂ nanofiber/carbon nanotubes (CNTs) composite as a matrix for the immobilization of redox protein onto glassy carbon electrode. The multiporous nanofiber (MPNFs) of SnO₂ is synthesized by electrospinning technique from the tin precursor. This nanofiber shows high surface area and good electrical conductivity. The SnO₂ nanofiber/CNT composite increases the efficiency of biomolecule loading due to its high surface area. The morphology of the nanofiber has been evaluated by scanning electron microscopy (SEM). Cyclic Voltammetry and amperometry technique are employed to study and optimize the performance of the fabricated electrode. A direct electron transfer between the protein's redox centre and the glassy carbon electrode is established after fabrication of the electrode. The fabricated electrode shows excellent electrocatalytic reduction to H₂O₂. The catalysis currents increases linearly to the H₂O₂ concentration in a wide range of 1.0 10^-6-1.4×10^-4M and the lowest detection limit was 30nM (S/N=3). Moreover, the biosensor showed a rapid response to H₂O₂, a good stability and reproducibility.