Due to the increasing number of people with diabetes in the world, as well as the time-consuming and expensive clinical methods, the use of biosensors for blood sugar detection has increased. One of the most important features of these sensors is their measurement accuracy and high speed of operation. In recent years, various methods with different functions have been introduced in this field, including spectrophotometry, electrochemical, chemiluminescence, photoelectric, Raman spectroscopy and photoelectrochemical (PEC) methods. Photoelectrochemistry includes electrochemical techniques with photocatalysis to facilitate the separation of photoelectron-hole produced in semiconductor nanoparticles, leading to increased photocatalytic efficiency of biosensors. Titanium dioxide-based sensors are the most promising systems for use in biosensors due to their low cost, non-toxicity, and chemical stability. Today, by using different methods, including creating black titanium dioxide structures in the manufacture of biosensors, the performance of biosensors made of titanium has been improved. Also, due to the disadvantages of enzyme-based biosensors, which can be mentioned as high cost, low stability, and other issues, nowadays non-enzymatic photoelectrochemical biosensors are welcomed. The purpose of this research is to construct a non-enzymatic biosensor based on black titanium oxide nanotubes and eva‎luate its photoelectrochemical behavior in order to detect glucose. In this regard, first, black titanium oxide nanotubes were formed by anodizing method, and then they were eva‎luated by X-ray diffraction and field emission electron microscopy, which shows the formation of black titanium oxide nanotubes on the surface of titanium foil. By conducting electrochemical tests such as Mott-Schottky and electrochemical impedance spectroscopy as well as open circuit potential test, it was found that black titanium oxide nanotubes performed better than white titanium oxide nanotubes in terms of charge carrier transfer and electron-hole recombination. In order to eva‎luate the sensitivity of the biosensor made using black titanium oxide nanotubes to glucose, electrochemical tests such as cyclic voltammetry and chronoamperometry were used in the presence of AM1/5G standard light with a power of 1000W/m2 and in the absence of standard light. The results showed that the glucose concentration is linear in the range of 0 to 15 mM, that the sensitivity of this biosensor in the presence of standard light to detect glucose is 14.172 μA/mMcm2, and the lowest detection rate is 0.497 mM. Also, by conducting selectivity tests in the presence of factors such as ascorbic acid, uric acid, sucrose and fructose, it was found that these substances did not significantly affect the amount of current received from glucose oxidation. Also, the reproducibility of the biosensor was eva‎luated by performing the chronoamperometry test, which showed that after 10 tests, the amount of received current decreased by 3.5%. The obtained results show the proper performance of this non-enzymatic biosensor compared to non-enzymatic biosensors and also the low cost of its production.

مهران نحوي

كيوان رئيسي , عليرضا علافچيان