Tuning electrocatalytic activity of Co3O4 nanosheets using CdS nanoparticles for highly sensitive non-enzymatic cholesterol biosensor

The accurate measurement of cholesterol in clinical diagnosis is very important for precise monitoring of multiple disease biomarkers. The increased level of cholesterol in the human body results in various life-threatening diseases. This leads to a top-notch priority for designing and fabricating a novel highly stable and reliable electrocatalyst for the measurement of cholesterol. In this work, Co3O4 nanosheets loaded with various amounts of CdS NPs (0.02, 0.026 and 0.033 mg) are prepared combining hydrothermal process and modified SILAR method. The developed Co3O4@CdS-3 (0.026 mg) electrode demonstrates excellent sensing capability towards cholesterol in a wide linear range from 250 to 5000 mu M. The electrode shows an outstanding high sensitivity of 13564.8 mu A mM-1 cm-2 which is much larger than the previously reported nanomaterials based non-enzymatic cholesterol biosensors. The Co3O4@CdS-3 exhibits lower detection limit of 0.001 mu M with good reproducibility for a period of 4 weeks and good selectivity. Moreover, the electrode displays good sensitivity towards cholesterol detection in the real samples, suggesting a new path to design and develop Co3O4@CdS-based extremely sensitive non-enzymatic biosensors for practical utilization.