طراحي و ساخت زيست حسگر الكتروشيميايي دوقطبي بسته براي اندازه‌گيري انسولين

Designing an‎d Fabrication of Closed Bipolar Electrochemical Biosensor for Insulin Measurement

شيمي معدني

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.

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