Ultrasensitive electrochemical biosensor based on MWCNT/Co3O4 nanocomposite for the nitric oxide determination

Nitric Oxide (NO) is a biomolecule that fulfils numerous vital functions in organisms. It serves as a potent vasodilator in the cardiovascular system. Consequently, its precise identification and measurement are essential for comprehending health and illness conditions. The electrochemical biosensor in this study was designed based on a nanocomposite of multi-walled Carbon nanotubes and Cobalt Oxide nanoparticles (MWCNT/Co 3 O 4 ), which function as an electrode surface modifier and facilitate the immobilization of hemoglobin (Hb) on the surface of the glassy carbon electrode (GCE) as a bio-recognition element. MWCNTs presented a large active surface on the electrode surface. Also, Co 3 O 4 nanoparticles facilitated the uniform arrangement of MWCNTs in nanocomposite structure. This biosensor measured different concentrations of NO in laboratory samples under optimal experimental conditions with high sensitivity. It showed a wide linear response range from 0.02 to 15 μM and a limit of detection (LOD) of 0.0085 μM for NO determination. In addition, the biosensor presented in this work showed acceptable reproducibility, high stability, and suitable selectivity in the presence of interfering substances.