Surface modification of electrospun spherical activated carbon for a high-performance biosensor electrode

A glucose sensor electrode was prepared from electrospun spherical-type carbon materials. The glucose oxidase (GOD) enzyme was immobilized on a prepared electrode for efficient glucose sensing. The GOD immobilization was maximized by enlarged sites of carbon electrode and improved interfacial affinity between the carbon surface and the GOD achieved via physical activation and oxyfluorination, respectively. The specific surface area was enlarged significantly, by over 42 fold, through physical activation. In addition, the hydrophobic carbon surface was modified with hydrophilic functional groups by direct oxyfluorination for improved interfacial affinity between the carbon and GOD. Accordingly, the GOD immobilization improved significantly by approximately 9 fold. The glucose sensor was evaluated by amperometric measurements and cyclic voltammetry. The measured current increased with higher glucose concentrations based on the effects of the developed pore structure and the introduced hydrophilic functional groups. The enzymatic kinetics were also studied using the Lineweaver–Burk equation. The sensitivity of the glucose sensor was improved by approximately 3 fold with increased maximum current, whereas the GOD enzyme activity was diminished by efficient GOD immobilization. Conclusively, a high-performance glucose sensor was obtained using an electrospun spherical-type carbon material due to efficient GOD enzyme immobilization.