Carbon Nanotubes Electrode Engineering for Nonenzymatic Electrochemical Biosensing: A Comparative Study of Fibrous and Powdered Architectures

Ascorbic acid (AA), uric acid (UA), and dopamine (DA) are associated with significant importance in physiological domains, including metabolism process, renal functioning, and central nervous system, respectively. Their precise electrochemical sensing is emerging as the most effective detection method, offering broad applications. This study highlights the mechanistic behavior of carbon nanotubes with two different morphologies, as electrode materials for the detection of selected biomolecules. The electrocatalytic behavior of nanotubes as powder versus fiber was investigated via cyclic voltammetry for the detailed electron transfer mechanism. CNT fiber electrode demonstrated a wide detection range of 16 mM for AA and 8 mM for UA, with high sensitivities of 29.58, 40, and 35 µAmM −1 for AA, UA, and DA, respectively. In contrast, the CNTP@GCE exhibited a detection range of 12 mM for AA and 14 mM for UA, with a lower sensitivity of 5.9 µAmM −1 for UA but a higher sensitivity of 30 µAmM −1 for AA.