CNTs/Graphene Oxide-Nickel Phosphate Nanocomposite-Based Electrochemical Sensor for Detecting H2O2 in Human Serum

Monitoring H2O2 levels in human serum is vital as it is a biomarker for oxidative stress-induced diseases and neurodegenerative disorders. Thus, an efficient electrochemical sensor is developed for detecting H2O2 in real human serum samples. The sensor is fabricated by modifying the GC surface with two consecutive thin layers namely carbon nanotubes (CNTs), and graphene oxide-nickel phosphate composite (GRO-NIPO). Under optimized conditions, the H2O2 sensor in human serum shows excellent catalytic effect in the concentration range (7 nM to 600 & mu;M) with low detection limit 0.55 nM in the low range (7 nM to 1 & mu;M). The combined effect of the catalytic activity of GRO-NIPO nanocomposite and the large conductive surface area of CNTs improve the sensor's performance. The negative reduction potential of H2O2 at -570 mV improves the anti-interference ability of the H2O2 sensor toward common interfering species in biological fluids. The layered modified electrode offers good sensitivity and low detection limit for H2O2 compared to other modified electrodes and some methods cited in the literature. Besides, the H2O2 sensor exhibits stable response over four weeks, excellent selectivity, reproducibility, repeatability, and steadiness. The reliability test of the sensor in serum sample shows good recovery of H2O2.