Label-free electrochemical aptasensor for ultrasensitive thrombin detection using graphene nanoplatelets and carbon nano onion-based nanocomposite

Abstract

Thrombin (TB) is a protease enzyme functioning in the blood coagulation cascade. It plays an important function in a number of diseases, including thromboembolic disease, Alzheimer's disease, and cancer.Therefore, precise, and sensitive detection of TB in clinical samples is of utmost importance. In this work, we have first synthesized a nanocomposite comprised of carboxyl-functionalized graphene nanoplatelets (GNPs), carbon nano-onions (CNOs), and chitosan (CS), which was used to develop an electrochemical aptasensor for selective detection of TB. This nanocomposite modified GCE exhibited a remarkable electrochemical response and a greater surface area (216 %) than the bare GCE. The morphology of the nanomaterials and nanocomposite were characterized using FESEM, TEM, and Energy-Dispersive X-ray Spectroscopy (EDS). The Layer-by-layer fabrication of the aptasensor was studied using the CV and DPV in Fe[CN]6]3/4− redox probeat pH 7.4. The designed aptasensor displayed sensitive detection of TB from 26.74 pM to 26.74 fM with a LOD of 8.61fM. Finally, this aptasensor showed promising potential in the quantitative determination of TB in human serum. This proposed aptasensor displayed excellent sensitivity, high specificity, and satisfactory reproducibility and can be useful in biomedical applications as well as for clinical purposes.