Carbon Black Nanoparticles-Functionalized NiFe-Layered Double Hydroxide Nanosheets as Nanoenzymes for the Electrochemical Sensing of Norepinephrine

Norepinephrine (NE) is widely utilized in diagnosing pheochromocytoma and paraganglioma and has demonstrated clinical relevance in conditions such as hypertension and heart failure. As a potential biomarker, it holds diagnostic value for nervous system diseases, including Alzheimer’s disease, psychiatric illnesses such as depression, and some metabolic disorders. Consequently, the precise measurement of NE in body fluids and tissues is of paramount importance. In the study, a nanoenzyme-powered electrochemical sensor with high sensitivity and specificity was developed based on carbon black nanoparticle-decorated NiFe-layered double hydroxide nanosheets (NiFe LDH-CB). The peak current changes caused by NE oxidation were analyzed by utilizing differential pulse voltammetry. A range of techniques, such as transmission electron microscopy, X-ray diffraction, and others, were used to evaluate the nanoenzyme’s properties. The sensor demonstrated a linear response range from 0.1–100 μM (R2 = 0.99531) and could detect as low as 3 nM. The remarkable performances, such as selectivity, stability, and anti-interference performance, were clearly exhibited. In rat serum samples, the sensor achieved recoveries of 90–110% for NE concentrations of 0.1, 1, and 10 μM, with relative standard deviations (RSD) of 0.77%–4.89 (N = 3). Our investigation highlights the potential of nanoenzyme-based sensors for accurate and reliable NE detection in clinical applications.