چكيده لاتين
The development of electrochemical biosensors capable of detecting biomolecules such as insulin with lower cost, higher speed, and greater sensitivity compared to conventional measurement methods represents one of the key needs and major challenges in the field of modern diagnostics. Considering the vital role of insulin in blood glucose regulation and the importance of its accurate monitoring in diabetic patients, the design and fabrication of systems capable of detecting this hormone at very low concentrations in a rapid and precise manner is of particular significance.
In this study, a closed bipolar electrochemical biosensor based on the measurement of current passing through a bipolar electrode was designed, fabricated, and evaluated for the detection and quantification of insulin. In the sensor cell, a graphite electrode was used as the bipolar electrode, which was surface modified with nickel oxide nanoparticles and subsequently functionalized with guanine as the biorecognition molecule. This surface modification led to improved electron transfer and the formation of more specific interactions between the sensor surface and insulin molecules.
In the reporter cell, potassium hexacyanoferrate (K₃[Fe(CN)₆]) was employed as the reporter species. In addition, stainless steel driving electrodes were selected due to their availability, high chemical resistance, and low cost, making them an efficient and economical choice. To achieve optimal performance, the concentrations of modifiers, deposition time, and applied potential were systematically investigated and optimized. Subsequently, the passing current was converted to voltage and measured using an analog-to-digital converter (ADC) from the bipolar system, and the calibration curve of the sensor response was plotted.Experimental results demonstrated that the fabricated sensor exhibited a wide linear range from 10⁻⁶ to 10⁻¹² molar, with a limit of detection of 0.96 picomolar and a limit of quantification of 2.90 picomolar for insulin. These values indicate the sensor’s high capability to detect insulin at physiological concentrations found in the human body. Furthermore, the studies on signal stability and response repeatability confirmed that the developed system possesses stable, accurate, and reliable performance over time.
Overall, the findings of this research indicate that the proposed electrochemical biosensor can serve as a promising platform for the development of portable, rapid, and cost-effective insulin monitoring devices. Ease of fabrication, low material cost, high sensitivity, and excellent selectivity are among the key advantages of this system.
