Functionalized single-layered titanium carbide MXene based biosensor for selective H2O2 detection using covalently immobilized horseradish peroxidase

Abstract

Hydrogen peroxide (H2O2) plays a significant role in biological and environmental systems. Therefore, it is crucial to develop an efficient biosensor towards H2O2 determination, which is important in environmental monitoring and biomedical diagnostics. In this work, we have synthesized an amine functionalized S-Ti3C2Tx MXene (NH2-S-Ti3C2Tx), which was modified over a glassy carbon electrode (GCE) to construct NH2-S-Ti3C2Tx/GCE. Thus obtained NH2-S-Ti3C2Tx/GCE was utilized as a platform for the covalent cross linking of water-soluble horseradish peroxidase (HRP) enzyme through glutaraldehyde coupling reaction, to attain (HRP/NH2-S-Ti3C2Tx/GCE). The fabricated HRP/NH2-S-Ti3C2Tx/GCE biosensor demonstrated a welldefined redox peak with a formal potential of -0.45 V, corresponding to the Fe III /Fe II redox center of HRP. Additionally, the designed biosensor has been employed towards the electrocatalytic detection of H2O2 under both static and dynamic conditions. The HRP/NH2-S-Ti3C2Tx/GCE sensor displayed a broad linear range of 20 μM to 1160 μM with a low limit of detection (LOD) of 5.3 μM and a high sensitivity of 0.798 μA mM-1 cm-2 and was successfully employed towards real-time detection of H2O2. The superior electrochemical properties of the fabricated sensor could be ascribed to the covalent immobilization of HRP over NH2-S-Ti3C2Tx.