Sensitive electrochemical biosensing of H2O2 based on cobalt nanoparticles synthesised in iron storage protein molecules, ferritin

In this report, a highly sensitive electrochemical biosensor based on cobaltferritin immobilised on a self-assembled monolayer modified gold electrode for determination of hydrogen peroxide (H₂O₂) in phosphate buffer solution (pH 7.5) was investigated. The modified electrode showed excellent electrochemical activity for oxidation of H₂O₂. The response to H₂O₂ on the modified electrode was examined using linear sweep and differential pulse voltammetries. In phosphate buffer (pH 7.5, 0.1 M), the fabricated biosensor exhibited a linear dependence (R = 0.989) on the concentration of H₂O₂ from 2.49 × 10^-9 to 1.91 × 10^-8 M, a high sensitivity of -0.4099 μA/nM and detection limit of 2.48 × 10^-9 based on a signal-to-noise ratio of 3. Charge transfer coefficient (α) and the exchange current (i₀) of oxidation for H₂O₂ were found to be 0.57 and 7.55 A, respectively. It has been shown that, this modified electrode is able to determine H₂O₂ with a high sensitivity, low detection limit and high selectivity.