Towards a dual in-line electrochemical biosensor for the determination of glucose and hydrogen peroxide

Herein, we report the development of a sensitive and selective dual mode electrochemical platform for the detection of glucose and H₂O₂. The platform is based on tungsten and gold microwire electrodes decorated with gold nanoparticles (AuNPs) and colloidal platinum (colloidal-Pt), respectively. The nanostructured AuNPs electrode was used as a support matrix for the immobilization of horseradish peroxidase (HRP) and the colloidal-Pt served as the non-enzymatic glucose biosensor in the construction of a dual in-line electrochemical biosensor that provides a microenvironment for HRP and a pathway for analyte diffusion via the high surface area. The dual-mode approach allows for the simultaneous detection of glucose and H₂O₂. The glucose biosensor exhibited a dynamic linear range of 0.5 mM to 8 mM glucose. Linearity for H₂O₂ was up to 70 μM. Operational stability resulted in 75% of the initial biosensor response after 27 days. The dual in-line biosensor showed good sensitivity of 0.403 mA mM^-1 cm^-2 for glucose and 0.193 mA mM^-1 cm^-2 for H₂O₂ in addition to good anti-interference ability. Thus, the low-cost and simple dual in-line biosensor can be used for the real-time detection of glucose and H₂O₂ in the clinical, biological and environmental fields.