Tailored electrochemical biosensor with poly-diallydimethylammonium chloride-functionalised multiwalled carbon nanotubes/gold nanoparticles/manganese dioxide, and haemoglobin for sensitive hydrogen peroxide detection

A very sensitive electrochemical biosensor, with haemoglobin (Hb) as its basis, has been created to quantify hydrogen peroxide (H2O2), an essential marker in environmental monitoring, food safety, and medical diagnosis. The sensor uses a simple, eco-friendly preparation method. Hb was immobilised on manganese dioxide nanostructure/gold nanoparticles/ poly-diallydimethylammonium chloride-functionalized multiwalled carbon nanotubes (PDDA-MWCNT/AuNP/MnO2), characterized using various techniques: amperometry, voltammetry, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Nafion was used as a binder membrane to preserve the biological and electrochemical properties of the protein on the modified electrode. In comparison to earlier research, the novel biosensor had a lower detection limit (1.83 μM) and a limit of quantification (6.11 μM) (S/N = 3) for H2O2. It also exhibited notable reproducibility, long-term stability, and repeatability. It was effectively used to measure the amount of H2O2 in cow milk and orange juice, yielding recoveries in the order of 98.90 to 99.53% with RSDs less than 5.0%, which makes it a promising biosensor for food control.